github-forks
/
FreeRTOS-Kernel
mirror of https://github.com/FreeRTOS/FreeRTOS-Kernel.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity

RISC-V: Add RV32E / FPU support for GCC (#140)

Browse Source 
* Change vPortSetupTimerInterrupt in order to have 64bits access on rv64

* Support RV32E - RISC-V architecture (GCC)

Signed-off-by: Emmanuel Puerto <emmanuel.puerto@sifive.com>

* Support FPU - RISC-V architecture (GCC)

Signed-off-by: Emmanuel Puerto <emmanuel.puerto@sifive.com>

* Fix interrupt managment and FPU initialization
pull/161/head
Emmanuel Puerto 4 years ago committed by GitHub
parent 524e78d58b
commit 0037a6c574
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 697 additions and 301 deletions
Show Stats Download Patch File Download Diff File

137
portable/GCC/RISC-V/port.c
Unescape Escape View File

@ -25,9 +25,11 @@
* 1 tab == 4 spaces!
*/
/*-----------------------------------------------------------
* Implementation of functions defined in portable.h for the RISC-V RV32 port.
*----------------------------------------------------------*/
/* ------------------------------------------------------------------
* This file is part of the FreeRTOS distribution and was contributed
* to the project by SiFive
* ------------------------------------------------------------------
*/
/* Scheduler includes. */
#include "FreeRTOS.h"
@ -118,31 +120,69 @@ task stack, not the ISR stack). */
#if( configMTIME_BASE_ADDRESS != 0 ) && ( configMTIMECMP_BASE_ADDRESS != 0 )
void vPortSetupTimerInterrupt( void )
{
uint32_t ulCurrentTimeHigh, ulCurrentTimeLow;
volatile uint32_t * const pulTimeHigh = ( volatile uint32_t * const ) ( ( configMTIME_BASE_ADDRESS ) + 4UL ); /* 8-byte typer so high 32-bit word is 4 bytes up. */
volatile uint32_t * const pulTimeLow = ( volatile uint32_t * const ) ( configMTIME_BASE_ADDRESS );
volatile uint32_t ulHartId;
__asm volatile( "csrr %0, mhartid" : "=r"( ulHartId ) );
pullMachineTimerCompareRegister = ( volatile uint64_t * ) ( ullMachineTimerCompareRegisterBase + ( ulHartId * sizeof( uint64_t ) ) );
do
{
ulCurrentTimeHigh = *pulTimeHigh;
ulCurrentTimeLow = *pulTimeLow;
} while( ulCurrentTimeHigh != *pulTimeHigh );
ullNextTime = ( uint64_t ) ulCurrentTimeHigh;
ullNextTime <<= 32ULL; /* High 4-byte word is 32-bits up. */
ullNextTime |= ( uint64_t ) ulCurrentTimeLow;
ullNextTime += ( uint64_t ) uxTimerIncrementsForOneTick;
*pullMachineTimerCompareRegister = ullNextTime;
/* Prepare the time to use after the next tick interrupt. */
ullNextTime += ( uint64_t ) uxTimerIncrementsForOneTick;
}
#if( __riscv_xlen == 32 )
void vPortSetupTimerInterrupt( void )
{
uint32_t ulCurrentTimeHigh, ulCurrentTimeLow;
volatile uint32_t * const pulTimeHigh = ( volatile uint32_t * const ) ( ( configMTIME_BASE_ADDRESS ) + 4UL ); /* 8-byte typer so high 32-bit word is 4 bytes up. */
volatile uint32_t * const pulTimeLow = ( volatile uint32_t * const ) ( configMTIME_BASE_ADDRESS );
volatile uint32_t * pulTimeCompareRegisterHigh;
volatile uint32_t * pulTimeCompareRegisterLow;
volatile uint32_t ulHartId;
__asm volatile ( "csrr %0, mhartid" : "=r" ( ulHartId ) );
/* pullMachineTimerCompareRegister is used by freertos_risc_v_trap_handler */
pullMachineTimerCompareRegister = ( volatile uint64_t * ) ( ullMachineTimerCompareRegisterBase + ( ulHartId * sizeof( uint64_t ) ) );
pulTimeCompareRegisterLow = ( volatile uint32_t * ) ( ullMachineTimerCompareRegisterBase + ( ulHartId * sizeof( uint64_t ) ) );
pulTimeCompareRegisterHigh = ( volatile uint32_t * ) ( ullMachineTimerCompareRegisterBase + ( ulHartId * sizeof( uint64_t ) ) + 4UL );
do
{
ulCurrentTimeHigh = *pulTimeHigh;
ulCurrentTimeLow = *pulTimeLow;
} while( ulCurrentTimeHigh != *pulTimeHigh );
ullNextTime = ( uint64_t ) ulCurrentTimeHigh;
ullNextTime <<= 32ULL; /* High 4-byte word is 32-bits up. */
ullNextTime |= (( uint64_t ) ulCurrentTimeLow );
ullNextTime += (( uint64_t ) uxTimerIncrementsForOneTick );
/* Per spec, the RISC-V MTIME/MTIMECMP registers are 64 bit,
* and are NOT internally latched for multiword transfers.
* Need to be careful about sequencing to avoid triggering
* spurious interrupts: For that set the high word to a max
* value first.
*/
*pulTimeCompareRegisterHigh = 0xFFFFFFFF;
*pulTimeCompareRegisterLow = (uint32_t)( ullNextTime );
*pulTimeCompareRegisterHigh = (uint32_t)( ullNextTime >> 32ULL );
/* Prepare the time to use after the next tick interrupt. */
ullNextTime += ( uint64_t ) uxTimerIncrementsForOneTick;
}
#endif /* __riscv_xlen == 32 */
#if( __riscv_xlen == 64 )
void vPortSetupTimerInterrupt( void )
{
volatile uint32_t * const pulTime = ( volatile uint32_t * const ) ( configMTIME_BASE_ADDRESS );
volatile uint32_t ulHartId;
__asm volatile ( "csrr %0, mhartid" : "=r" ( ulHartId ) );
pullMachineTimerCompareRegister = ( volatile uint64_t * ) ( ullMachineTimerCompareRegisterBase + ( ulHartId * sizeof( uint64_t ) ) );
ullNextTime = *pulTime;
ullNextTime += ( uint64_t ) uxTimerIncrementsForOneTick;
*pullMachineTimerCompareRegister = ullNextTime;
/* Prepare the time to use after the next tick interrupt. */
ullNextTime += ( uint64_t ) uxTimerIncrementsForOneTick;
}
#endif /* __riscv_xlen == 64 */
#endif /* ( configMTIME_BASE_ADDRESS != 0 ) && ( configMTIME_BASE_ADDRESS != 0 ) */
/*-----------------------------------------------------------*/
@ -178,20 +218,7 @@ extern void xPortStartFirstTask( void );
configure whichever clock is to be used to generate the tick interrupt. */
vPortSetupTimerInterrupt();
#if( ( configMTIME_BASE_ADDRESS != 0 ) && ( configMTIMECMP_BASE_ADDRESS != 0 ) )
{
/* Enable mtime and external interrupts. 1<<7 for timer interrupt, 1<<11
for external interrupt. _RB_ What happens here when mtime is not present as
with pulpino? */
__asm volatile( "csrs mie, %0" :: "r"(0x880) );
}
#else
{
/* Enable external interrupts. */
__asm volatile( "csrs mie, %0" :: "r"(0x800) );
}
#endif /* ( configMTIME_BASE_ADDRESS != 0 ) && ( configMTIMECMP_BASE_ADDRESS != 0 ) */
/* Enabling mtime and external interrupts will be made into xPortStartFirstTask function */
xPortStartFirstTask();
/* Should not get here as after calling xPortStartFirstTask() only tasks
@ -205,8 +232,26 @@ void vPortEndScheduler( void )
/* Not implemented. */
for( ;; );
}
/*-----------------------------------------------------------*/
#if( configENABLE_FPU == 1 )
void vPortSetupFPU( void )
{
#ifdef __riscv_fdiv
__asm__ __volatile__ (
"csrr t0, misa \n" /* Get misa */
"li t1, 0x10028 \n" /* 0x10028 = Q,F,D Quad, Single or Double precission floating point */
"and t0, t0, t1 \n"
"beqz t0, 1f \n" /* check if Q,F or D is present into misa */
"csrr t0, mstatus \n" /* Floating point unit is present so need to put it into initial state */
"lui t1, 0x2 \n" /* t1 = 0x1 << 12 */
"or t0, t0, t1 \n"
"csrw mstatus, t0 \n" /* Set FS to initial state */
"csrwi fcsr, 0 \n" /* Clear Floating-point Control and Status Register */
"1: \n"
:::
);
#endif /* __riscv_fdiv */
}
#endif /* configENABLE_FPU */
/*-----------------------------------------------------------*/

861
portable/GCC/RISC-V/portASM.S
Unescape Escape View File

@ -55,17 +55,56 @@
* registers.
*
*/
#if __riscv_xlen == 64
#define portWORD_SIZE 8
/* ------------------------------------------------------------------
* This file is part of the FreeRTOS distribution and was contributed
* to the project by SiFive
* ------------------------------------------------------------------
*/
#if( __riscv_xlen == 64 )
#define store_x sd
#define load_x ld
#elif __riscv_xlen == 32
#elif( __riscv_xlen == 32 )
#define store_x sw
#define load_x lw
#define portWORD_SIZE 4
#else
#error Assembler did not define __riscv_xlen
#endif
#endif /* ( __riscv_xlen == xx ) */
/* Nb registers to save */
#ifdef __riscv_32e
#define portasmNB_REGS_SAVED (16)
#else
#define portasmNB_REGS_SAVED (32)
#endif /* __riscv_32e */
#define portWORD_SIZE (__riscv_xlen / 8)
/* Number of FPU register */
#ifdef __riscv_fdiv
#define MSTATUS_FS 0x00006000 /* Floating-point Status */
#define MSTATUS_FS_OFF 0x00000000
#define MSTATUS_FS_INITIAL 0x00002000
#define MSTATUS_FS_CLEAN 0x00004000
#define MSTATUS_FS_DIRTY 0x00006000
#if __riscv_flen == 32
#define store_fpu fsw
#define load_fpu flw
#endif /* __riscv_flen == 32 */
#if __riscv_flen == 64
#define store_fpu fsd
#define load_fpu fld
#endif /* __riscv_flen == 64 */
#define portasmFPU_CONTEXT_SIZE (32)
#define portFPUWORD_SIZE (__riscv_flen / 8)
#else
#define portasmFPU_CONTEXT_SIZE (0)
#define portFPUWORD_SIZE (0)
#endif /* __riscv_fdiv */
#include "freertos_risc_v_chip_specific_extensions.h"
@ -85,20 +124,47 @@ definitions. */
#error freertos_risc_v_chip_specific_extensions.h must define portasmHAS_MTIME to either 1 (MTIME clock present) or 0 (MTIME clock not present). See https://www.FreeRTOS.org/Using-FreeRTOS-on-RISC-V.html
#endif
#ifndef portasmHANDLE_INTERRUPT
#error portasmHANDLE_INTERRUPT must be defined to the function to be called to handle external/peripheral interrupts. portasmHANDLE_INTERRUPT can be defined on the assembler command line or in the appropriate freertos_risc_v_chip_specific_extensions.h header file. https://www.FreeRTOS.org/Using-FreeRTOS-on-RISC-V.html
#ifndef portHANDLE_INTERRUPT
#error portHANDLE_INTERRUPT must be defined to the function to be called to handle external/peripheral interrupts.
#endif
#ifndef portHANDLE_EXCEPTION
#error portHANDLE_EXCEPTION must be defined to the function to be called to handle execptions.
#endif
#ifndef portasmHAS_SIFIVE_CLINT
#define portasmHAS_SIFIVE_CLINT 0
#endif
/* Only the standard core registers are stored by default. Any additional
registers must be saved by the portasmSAVE_ADDITIONAL_REGISTERS and
portasmRESTORE_ADDITIONAL_REGISTERS macros - which can be defined in a chip
specific version of freertos_risc_v_chip_specific_extensions.h. See the notes
at the top of this file. */
#define portCONTEXT_SIZE ( 30 * portWORD_SIZE )
/*
* To maintain RISCV ABI stack alignment requirements (16bytes)
* this data structure must be a MULTIPLE of 16 bytes in size.
* 32 Registers (for standard core) is 16byte aligned :)
* We add space to save additional information so it must be multiple of 4.
* mepc 33th register
* mstatus 34th register
* ruf 35th register
* ruf 36th register
*/
#define PORT_CONTEXT_mepcIDX (portasmNB_REGS_SAVED)
#define PORT_CONTEXT_mstatusIDX (portasmNB_REGS_SAVED + 1)
#define portasmLAST_BASE_REGS (portasmNB_REGS_SAVED + 4)
#define PORT_CONTEXT_lastIDX ((portasmNB_REGS_SAVED) + portasmADDITIONAL_CONTEXT_SIZE)
/* used in assembler, as byte offsets from the start of the context */
#define PORT_CONTEXT_xIDX(X) (X) /* index into "raw" for register x? */
#define PORT_CONTEXT_xOFFSET(X) (PORT_CONTEXT_xIDX(X) * portWORD_SIZE)
#define PORT_CONTEXT_mepcOFFSET (PORT_CONTEXT_mepcIDX * portWORD_SIZE)
#define PORT_CONTEXT_mstatusOFFSET (PORT_CONTEXT_mstatusIDX * portWORD_SIZE)
#define PORT_CONTEXT_rufOFFSET (PORT_CONTEXT_rufIDX * portWORD_SIZE)
#define PORT_CONTEXT_fpuOFFSET(X) ((X) * portFPUWORD_SIZE)
/* total size of the structure usable in ASM. */
#define portasmREGISTER_CONTEXT_WORDSIZE ((portasmLAST_BASE_REGS) * (portWORD_SIZE))
#define portasmADDITIONAL_CONTEXT_WORDSIZE ((portasmADDITIONAL_CONTEXT_SIZE) * (portWORD_SIZE))
#define portasmFPU_CONTEXT_WORDSIZE ((portasmFPU_CONTEXT_SIZE) * (portFPUWORD_SIZE))
.global xPortStartFirstTask
.global freertos_risc_v_trap_handler
@ -112,184 +178,422 @@ at the top of this file. */
.extern pullNextTime
.extern uxTimerIncrementsForOneTick /* size_t type so 32-bit on 32-bit core and 64-bits on 64-bit core. */
.extern xISRStackTop
.extern portasmHANDLE_INTERRUPT
.extern portHANDLE_INTERRUPT
.extern portHANDLE_EXCEPTION
/*-----------------------------------------------------------*/
.align 8
.func
freertos_risc_v_trap_handler:
addi sp, sp, -portCONTEXT_SIZE
store_x x1, 1 * portWORD_SIZE( sp )
store_x x5, 2 * portWORD_SIZE( sp )
store_x x6, 3 * portWORD_SIZE( sp )
store_x x7, 4 * portWORD_SIZE( sp )
store_x x8, 5 * portWORD_SIZE( sp )
store_x x9, 6 * portWORD_SIZE( sp )
store_x x10, 7 * portWORD_SIZE( sp )
store_x x11, 8 * portWORD_SIZE( sp )
store_x x12, 9 * portWORD_SIZE( sp )
store_x x13, 10 * portWORD_SIZE( sp )
store_x x14, 11 * portWORD_SIZE( sp )
store_x x15, 12 * portWORD_SIZE( sp )
store_x x16, 13 * portWORD_SIZE( sp )
store_x x17, 14 * portWORD_SIZE( sp )
store_x x18, 15 * portWORD_SIZE( sp )
store_x x19, 16 * portWORD_SIZE( sp )
store_x x20, 17 * portWORD_SIZE( sp )
store_x x21, 18 * portWORD_SIZE( sp )
store_x x22, 19 * portWORD_SIZE( sp )
store_x x23, 20 * portWORD_SIZE( sp )
store_x x24, 21 * portWORD_SIZE( sp )
store_x x25, 22 * portWORD_SIZE( sp )
store_x x26, 23 * portWORD_SIZE( sp )
store_x x27, 24 * portWORD_SIZE( sp )
store_x x28, 25 * portWORD_SIZE( sp )
store_x x29, 26 * portWORD_SIZE( sp )
store_x x30, 27 * portWORD_SIZE( sp )
store_x x31, 28 * portWORD_SIZE( sp )
csrr t0, mstatus /* Required for MPIE bit. */
store_x t0, 29 * portWORD_SIZE( sp )
portasmSAVE_ADDITIONAL_REGISTERS /* Defined in freertos_risc_v_chip_specific_extensions.h to save any registers unique to the RISC-V implementation. */
load_x t0, pxCurrentTCB /* Load pxCurrentTCB. */
store_x sp, 0( t0 ) /* Write sp to first TCB member. */
csrr a0, mcause
csrr a1, mepc
test_if_asynchronous:
srli a2, a0, __riscv_xlen - 1 /* MSB of mcause is 1 if handing an asynchronous interrupt - shift to LSB to clear other bits. */
beq a2, x0, handle_synchronous /* Branch past interrupt handing if not asynchronous. */
store_x a1, 0( sp ) /* Asynch so save unmodified exception return address. */
handle_asynchronous:
#if( portasmHAS_MTIME != 0 )
test_if_mtimer: /* If there is a CLINT then the mtimer is used to generate the tick interrupt. */
addi t0, x0, 1
slli t0, t0, __riscv_xlen - 1 /* LSB is already set, shift into MSB. Shift 31 on 32-bit or 63 on 64-bit cores. */
addi t1, t0, 7 /* 0x8000[]0007 == machine timer interrupt. */
bne a0, t1, test_if_external_interrupt
load_x t0, pullMachineTimerCompareRegister /* Load address of compare register into t0. */
load_x t1, pullNextTime /* Load the address of ullNextTime into t1. */
#if( __riscv_xlen == 32 )
/* Update the 64-bit mtimer compare match value in two 32-bit writes. */
li t4, -1
lw t2, 0(t1) /* Load the low word of ullNextTime into t2. */
lw t3, 4(t1) /* Load the high word of ullNextTime into t3. */
sw t4, 0(t0) /* Low word no smaller than old value to start with - will be overwritten below. */
sw t3, 4(t0) /* Store high word of ullNextTime into compare register. No smaller than new value. */
sw t2, 0(t0) /* Store low word of ullNextTime into compare register. */
lw t0, uxTimerIncrementsForOneTick /* Load the value of ullTimerIncrementForOneTick into t0 (could this be optimized by storing in an array next to pullNextTime?). */
add t4, t0, t2 /* Add the low word of ullNextTime to the timer increments for one tick (assumes timer increment for one tick fits in 32-bits). */
sltu t5, t4, t2 /* See if the sum of low words overflowed (what about the zero case?). */
add t6, t3, t5 /* Add overflow to high word of ullNextTime. */
sw t4, 0(t1) /* Store new low word of ullNextTime. */
sw t6, 4(t1) /* Store new high word of ullNextTime. */
#endif /* __riscv_xlen == 32 */
#if( __riscv_xlen == 64 )
/* Update the 64-bit mtimer compare match value. */
ld t2, 0(t1) /* Load ullNextTime into t2. */
sd t2, 0(t0) /* Store ullNextTime into compare register. */
ld t0, uxTimerIncrementsForOneTick /* Load the value of ullTimerIncrementForOneTick into t0 (could this be optimized by storing in an array next to pullNextTime?). */
add t4, t0, t2 /* Add ullNextTime to the timer increments for one tick. */
sd t4, 0(t1) /* Store ullNextTime. */
#endif /* __riscv_xlen == 64 */
load_x sp, xISRStackTop /* Switch to ISR stack before function call. */
jal xTaskIncrementTick
beqz a0, processed_source /* Don't switch context if incrementing tick didn't unblock a task. */
jal vTaskSwitchContext
j processed_source
test_if_external_interrupt: /* If there is a CLINT and the mtimer interrupt is not pending then check to see if an external interrupt is pending. */
addi t1, t1, 4 /* 0x80000007 + 4 = 0x8000000b == Machine external interrupt. */
bne a0, t1, as_yet_unhandled /* Something as yet unhandled. */
#ifdef __riscv_fdiv
.macro portSAVE_FpuReg
/* get FS field from mstatus */
li t0, MSTATUS_FS
csrr t1, mstatus
and t0, t1, t0
li t2, MSTATUS_FS_DIRTY
bne t2, t0, 1f
/* FS == dirty */
/* Make room for the additional FPU registers. */
addi sp, sp, -portasmFPU_CONTEXT_WORDSIZE
store_fpu f0, PORT_CONTEXT_fpuOFFSET(0)(sp) /* f0(ft0) FP temporary register */
store_fpu f1, PORT_CONTEXT_fpuOFFSET(1)(sp) /* f1(ft1) FP temporary register */
store_fpu f2, PORT_CONTEXT_fpuOFFSET(2)(sp) /* f2(ft2) FP temporary register */
store_fpu f3, PORT_CONTEXT_fpuOFFSET(3)(sp) /* f3(ft3) FP temporary register */
store_fpu f4, PORT_CONTEXT_fpuOFFSET(4)(sp) /* f4(ft4) FP temporary register */
store_fpu f5, PORT_CONTEXT_fpuOFFSET(5)(sp) /* f5(ft5) FP temporary register */
store_fpu f6, PORT_CONTEXT_fpuOFFSET(6)(sp) /* f6(ft6) FP temporary register */
store_fpu f7, PORT_CONTEXT_fpuOFFSET(7)(sp) /* f7(ft7) FP temporary register */
store_fpu f8, PORT_CONTEXT_fpuOFFSET(8)(sp) /* f8(fs0) FP Saved register */
store_fpu f9, PORT_CONTEXT_fpuOFFSET(9)(sp) /* f9(fs0) FP Saved register */
store_fpu f10, PORT_CONTEXT_fpuOFFSET(10)(sp) /* f10(fa0) FP arguments/return values register */
store_fpu f11, PORT_CONTEXT_fpuOFFSET(11)(sp) /* f11(fa1) FP arguments/return values register */
store_fpu f12, PORT_CONTEXT_fpuOFFSET(12)(sp) /* f12(fa2) FP arguments register */
store_fpu f13, PORT_CONTEXT_fpuOFFSET(13)(sp) /* f13(fa3) FP arguments register */
store_fpu f14, PORT_CONTEXT_fpuOFFSET(14)(sp) /* f14(fa4) FP arguments register */
store_fpu f15, PORT_CONTEXT_fpuOFFSET(15)(sp) /* f15(fa5) FP arguments register */
store_fpu f16, PORT_CONTEXT_fpuOFFSET(16)(sp) /* f16(fa6) FP arguments register */
store_fpu f17, PORT_CONTEXT_fpuOFFSET(17)(sp) /* f17(fa7) FP arguments register */
store_fpu f18, PORT_CONTEXT_fpuOFFSET(18)(sp) /* f18(fs2) FP Saved register */
store_fpu f19, PORT_CONTEXT_fpuOFFSET(19)(sp) /* f19(fs3) FP Saved register */
store_fpu f20, PORT_CONTEXT_fpuOFFSET(20)(sp) /* f20(fs4) FP Saved register */
store_fpu f21, PORT_CONTEXT_fpuOFFSET(21)(sp) /* f21(fs5) FP Saved register */
store_fpu f22, PORT_CONTEXT_fpuOFFSET(22)(sp) /* f22(fs6) FP Saved register */
store_fpu f23, PORT_CONTEXT_fpuOFFSET(23)(sp) /* f23(fs7) FP Saved register */
store_fpu f24, PORT_CONTEXT_fpuOFFSET(24)(sp) /* f24(fs8) FP Saved register */
store_fpu f25, PORT_CONTEXT_fpuOFFSET(25)(sp) /* f25(fs9) FP Saved register */
store_fpu f26, PORT_CONTEXT_fpuOFFSET(26)(sp) /* f26(fs10) FP Saved register */
store_fpu f27, PORT_CONTEXT_fpuOFFSET(27)(sp) /* f27(fs11) FP Saved register */
store_fpu f28, PORT_CONTEXT_fpuOFFSET(28)(sp) /* f28(ft8) FP temporary register */
store_fpu f29, PORT_CONTEXT_fpuOFFSET(29)(sp) /* f29(ft9) FP temporary register */
store_fpu f30, PORT_CONTEXT_fpuOFFSET(30)(sp) /* f30(ft10) FP temporary register */
store_fpu f31, PORT_CONTEXT_fpuOFFSET(31)(sp) /* f31(ft11) FP temporary register */
/* must set FS to clean */
csrc mstatus, t0
li t1, MSTATUS_FS_CLEAN
csrs mstatus, t1
1:
.endm
#else
.macro portSAVE_FpuReg
/* No fpu registers to save, so this macro does nothing. */
.endm
#endif /* __riscv_fdiv */
/*-----------------------------------------------------------*/
#endif /* portasmHAS_MTIME */
#ifdef __riscv_fdiv
.macro portRESTORE_FpuReg
/* get FS field from mstatus */
li t0, MSTATUS_FS
csrr t1, mstatus
and t0, t1, t0
li t2, MSTATUS_FS_OFF
beq t2, t0, 1f
/* FS != off */
csrs mstatus, t0
/* Remove space added for additional fpu registers. */
addi sp, sp, portasmFPU_CONTEXT_WORDSIZE
load_fpu f0, PORT_CONTEXT_fpuOFFSET(0)(sp) /* f0(ft0) FP temporary register */
load_fpu f1, PORT_CONTEXT_fpuOFFSET(1)(sp) /* f1(ft1) FP temporary register */
load_fpu f2, PORT_CONTEXT_fpuOFFSET(2)(sp) /* f2(ft2) FP temporary register */
load_fpu f3, PORT_CONTEXT_fpuOFFSET(3)(sp) /* f3(ft3) FP temporary register */
load_fpu f4, PORT_CONTEXT_fpuOFFSET(4)(sp) /* f4(ft4) FP temporary register */
load_fpu f5, PORT_CONTEXT_fpuOFFSET(5)(sp) /* f5(ft5) FP temporary register */
load_fpu f6, PORT_CONTEXT_fpuOFFSET(6)(sp) /* f6(ft6) FP temporary register */
load_fpu f7, PORT_CONTEXT_fpuOFFSET(7)(sp) /* f7(ft7) FP temporary register */
load_fpu f8, PORT_CONTEXT_fpuOFFSET(8)(sp) /* f8(fs0) FP Saved register */
load_fpu f9, PORT_CONTEXT_fpuOFFSET(9)(sp) /* f9(fs0) FP Saved register */
load_fpu f10, PORT_CONTEXT_fpuOFFSET(10)(sp) /* f10(fa0) FP arguments/return values register */
load_fpu f11, PORT_CONTEXT_fpuOFFSET(11)(sp) /* f11(fa1) FP arguments/return values register */
load_fpu f12, PORT_CONTEXT_fpuOFFSET(12)(sp) /* f12(fa2) FP arguments register */
load_fpu f13, PORT_CONTEXT_fpuOFFSET(13)(sp) /* f13(fa3) FP arguments register */
load_fpu f14, PORT_CONTEXT_fpuOFFSET(14)(sp) /* f14(fa4) FP arguments register */
load_fpu f15, PORT_CONTEXT_fpuOFFSET(15)(sp) /* f15(fa5) FP arguments register */
load_fpu f16, PORT_CONTEXT_fpuOFFSET(16)(sp) /* f16(fa6) FP arguments register */
load_fpu f17, PORT_CONTEXT_fpuOFFSET(17)(sp) /* f17(fa7) FP arguments register */
load_fpu f18, PORT_CONTEXT_fpuOFFSET(18)(sp) /* f18(fs2) FP Saved register */
load_fpu f19, PORT_CONTEXT_fpuOFFSET(19)(sp) /* f19(fs3) FP Saved register */
load_fpu f20, PORT_CONTEXT_fpuOFFSET(20)(sp) /* f20(fs4) FP Saved register */
load_fpu f21, PORT_CONTEXT_fpuOFFSET(21)(sp) /* f21(fs5) FP Saved register */
load_fpu f22, PORT_CONTEXT_fpuOFFSET(22)(sp) /* f22(fs6) FP Saved register */
load_fpu f23, PORT_CONTEXT_fpuOFFSET(23)(sp) /* f23(fs7) FP Saved register */
load_fpu f24, PORT_CONTEXT_fpuOFFSET(24)(sp) /* f24(fs8) FP Saved register */
load_fpu f25, PORT_CONTEXT_fpuOFFSET(25)(sp) /* f25(fs9) FP Saved register */
load_fpu f26, PORT_CONTEXT_fpuOFFSET(26)(sp) /* f26(fs10) FP Saved register */
load_fpu f27, PORT_CONTEXT_fpuOFFSET(27)(sp) /* f27(fs11) FP Saved register */
load_fpu f28, PORT_CONTEXT_fpuOFFSET(28)(sp) /* f28(ft8) FP temporary register */
load_fpu f29, PORT_CONTEXT_fpuOFFSET(29)(sp) /* f29(ft9) FP temporary register */
load_fpu f30, PORT_CONTEXT_fpuOFFSET(30)(sp) /* f30(ft10) FP temporary register */
load_fpu f31, PORT_CONTEXT_fpuOFFSET(31)(sp) /* f31(ft11) FP temporary register */
/* must set FS to clean */
csrc mstatus, t0
li t1, MSTATUS_FS_CLEAN
csrs mstatus, t1
1:
.endm
#else
.macro portRESTORE_FpuReg
/* No fpu registers to restore, so this macro does nothing. */
.endm
#endif /* __riscv_fdiv */
/*-----------------------------------------------------------*/
load_x sp, xISRStackTop /* Switch to ISR stack before function call. */
jal portasmHANDLE_INTERRUPT /* Jump to the interrupt handler if there is no CLINT or if there is a CLINT and it has been determined that an external interrupt is pending. */
j processed_source
.macro portSAVE_BaseReg
/* Make room for the registers. */
addi sp, sp, -portasmREGISTER_CONTEXT_WORDSIZE
store_x x1, PORT_CONTEXT_xOFFSET(1)(sp) /* x1(ra) Return address */
/* x2(sp) ***** Should be save ouside this macro */
store_x x3, PORT_CONTEXT_xOFFSET(3)(sp) /* x3(gp) Global pointer */
store_x x4, PORT_CONTEXT_xOFFSET(4)(sp) /* x4(tp) Thread pointer */
store_x x5, PORT_CONTEXT_xOFFSET(5)(sp) /* x5(t0) Temporary register */
store_x x6, PORT_CONTEXT_xOFFSET(6)(sp) /* x6(t1) Temporary register*/
store_x x7, PORT_CONTEXT_xOFFSET(7)(sp) /* x7(t2) Temporary register */
store_x x8, PORT_CONTEXT_xOFFSET(8)(sp) /* x8(s0/fp) Saved register/Frame pointer */
store_x x9, PORT_CONTEXT_xOFFSET(9)(sp) /* x9(s1) Saved register */
store_x x10, PORT_CONTEXT_xOFFSET(10)(sp) /* x10(a0) Function argument */
store_x x11, PORT_CONTEXT_xOFFSET(11)(sp) /* x11(a1) Function argument */
store_x x12, PORT_CONTEXT_xOFFSET(12)(sp) /* x12(a2) Function argument */
store_x x13, PORT_CONTEXT_xOFFSET(13)(sp) /* x13(a3) Function argument */
store_x x14, PORT_CONTEXT_xOFFSET(14)(sp) /* x14(a4) Function argument */
store_x x15, PORT_CONTEXT_xOFFSET(15)(sp) /* x15(a5) Function argument */
#ifndef __riscv_32e
store_x x16, PORT_CONTEXT_xOFFSET(16)(sp) /* x16(a6) Function arguments */
store_x x17, PORT_CONTEXT_xOFFSET(17)(sp) /* x17(a7) Function arguments */
store_x x18, PORT_CONTEXT_xOFFSET(18)(sp) /* x18(s2) Saved register */
store_x x19, PORT_CONTEXT_xOFFSET(19)(sp) /* x19(s3) Saved register */
store_x x20, PORT_CONTEXT_xOFFSET(20)(sp) /* x20(s4) Saved register */
store_x x21, PORT_CONTEXT_xOFFSET(21)(sp) /* x21(s5) Saved register */
store_x x22, PORT_CONTEXT_xOFFSET(22)(sp) /* x22(s6) Saved register */
store_x x23, PORT_CONTEXT_xOFFSET(23)(sp) /* x23(s7) Saved register */
store_x x24, PORT_CONTEXT_xOFFSET(24)(sp) /* x24(s8) Saved register */
store_x x25, PORT_CONTEXT_xOFFSET(25)(sp) /* x25(s9) Saved register */
store_x x26, PORT_CONTEXT_xOFFSET(26)(sp) /* x26(s10) Saved register */
store_x x27, PORT_CONTEXT_xOFFSET(27)(sp) /* x27(s11) Saved register */
store_x x28, PORT_CONTEXT_xOFFSET(28)(sp) /* x28(t3) Temporary register */
store_x x29, PORT_CONTEXT_xOFFSET(29)(sp) /* x29(t4) Temporary register */
store_x x30, PORT_CONTEXT_xOFFSET(30)(sp) /* x30(t5) Temporary register */
store_x x31, PORT_CONTEXT_xOFFSET(31)(sp) /* x31(t6) Temporary register */
#endif /* __riscv_32e */
/* Save mcause, mepc & mstatus state */
csrr a4, mepc
csrr a5, mstatus /* Required for MPIE bit. */
store_x a4, PORT_CONTEXT_mepcOFFSET(sp)
store_x a5, PORT_CONTEXT_mstatusOFFSET(sp)
.endm
/*-----------------------------------------------------------*/
handle_synchronous:
addi a1, a1, 4 /* Synchronous so updated exception return address to the instruction after the instruction that generated the exeption. */
store_x a1, 0( sp ) /* Save updated exception return address. */
.macro portRESTORE_BaseReg
/* Restore mepc & mstatus state */
load_x t0, PORT_CONTEXT_mepcOFFSET(sp)
load_x t1, PORT_CONTEXT_mstatusOFFSET(sp)
csrw mepc, t0
csrw mstatus, t1
load_x x1, PORT_CONTEXT_xOFFSET(1)(sp) /* x1(ra) Return address */
/* x2(sp) ***** Should be save ouside this macro */
load_x x3, PORT_CONTEXT_xOFFSET(3)(sp) /* x3(gp) Global pointer */
load_x x4, PORT_CONTEXT_xOFFSET(4)(sp) /* x4(tp) Thread pointer */
load_x x5, PORT_CONTEXT_xOFFSET(5)(sp) /* x5(t0) Temporary register */
load_x x6, PORT_CONTEXT_xOFFSET(6)(sp) /* x6(t1) Temporary register*/
load_x x7, PORT_CONTEXT_xOFFSET(7)(sp) /* x7(t2) Temporary register */
load_x x8, PORT_CONTEXT_xOFFSET(8)(sp) /* x8(s0/fp) Saved register/Frame pointer */
load_x x9, PORT_CONTEXT_xOFFSET(9)(sp) /* x9(s1) Saved register */
load_x x10, PORT_CONTEXT_xOFFSET(10)(sp) /* x10(a0) Function argument */
load_x x11, PORT_CONTEXT_xOFFSET(11)(sp) /* x11(a1) Function argument */
load_x x12, PORT_CONTEXT_xOFFSET(12)(sp) /* x12(a2) Function argument */
load_x x13, PORT_CONTEXT_xOFFSET(13)(sp) /* x13(a3) Function argument */
load_x x14, PORT_CONTEXT_xOFFSET(14)(sp) /* x14(a4) Function argument */
load_x x15, PORT_CONTEXT_xOFFSET(15)(sp) /* x15(a5) Function argument */
#ifndef __riscv_32e
load_x x16, PORT_CONTEXT_xOFFSET(16)(sp) /* x16(a6) Function arguments */
load_x x17, PORT_CONTEXT_xOFFSET(17)(sp) /* x17(a7) Function arguments */
load_x x18, PORT_CONTEXT_xOFFSET(18)(sp) /* x18(s2) Saved register */
load_x x19, PORT_CONTEXT_xOFFSET(19)(sp) /* x19(s3) Saved register */
load_x x20, PORT_CONTEXT_xOFFSET(20)(sp) /* x20(s4) Saved register */
load_x x21, PORT_CONTEXT_xOFFSET(21)(sp) /* x21(s5) Saved register */
load_x x22, PORT_CONTEXT_xOFFSET(22)(sp) /* x22(s6) Saved register */
load_x x23, PORT_CONTEXT_xOFFSET(23)(sp) /* x23(s7) Saved register */
load_x x24, PORT_CONTEXT_xOFFSET(24)(sp) /* x24(s8) Saved register */
load_x x25, PORT_CONTEXT_xOFFSET(25)(sp) /* x25(s9) Saved register */
load_x x26, PORT_CONTEXT_xOFFSET(26)(sp) /* x26(s10) Saved register */
load_x x27, PORT_CONTEXT_xOFFSET(27)(sp) /* x27(s11) Saved register */
load_x x28, PORT_CONTEXT_xOFFSET(28)(sp) /* x28(t3) Temporary register */
load_x x29, PORT_CONTEXT_xOFFSET(29)(sp) /* x29(t4) Temporary register */
load_x x30, PORT_CONTEXT_xOFFSET(30)(sp) /* x30(t5) Temporary register */
load_x x31, PORT_CONTEXT_xOFFSET(31)(sp) /* x31(t6) Temporary register */
#endif /* __riscv_32e */
.endm
/*-----------------------------------------------------------*/
test_if_environment_call:
li t0, 11 /* 11 == environment call. */
bne a0, t0, is_exception /* Not an M environment call, so some other exception. */
load_x sp, xISRStackTop /* Switch to ISR stack before function call. */
jal vTaskSwitchContext
j processed_source
.align 8
.func
freertos_risc_v_trap_handler:
/* We do not know if this is an ASYNC or SYNC
* If ASYNC, it is a normal interrupt
* and the stack pointer is assumed good.
* else (SYNC)
* We could be here due to a bus fault.
*/
csrw mscratch, t0
csrr t0, mcause
blt t0, x0, handle_interrupt
handle_exception:
/* mscratch = old t0
* t0 = mcause
* mcause = small number 0..16
* 0 Instruction address misaligned
* 1 Instruction access fault
* 2 Illegal instruction
* 3 Breakpoint
* 4 Load address misaligned
* 5 Load access fault
* 6 Store/AMO address misaligned
* 7 Store/AMO access fault
* 8 Environment call from U-mode
* 9 Environment call from S-mode
* 10 Reserved
* 11 Environment call from M-mode
* 12 Instruction page fault
* 13 Load page fault
* 14 Reserved
* 15 Store/AMO page fault
* ≥16 Reserved
*
* if( mcause between 8 and 11 ) we are good - ecall
* else: problem
*/
addi t0, t0, -8
blt t0, x0, is_exception /* mcause < 8, must be fault */
addi t0, t0, -4
blt t0, x0, ecall_yield
is_exception:
csrr t0, mcause /* For viewing in the debugger only. */
csrr t1, mepc /* For viewing in the debugger only */
csrr t2, mstatus
j is_exception /* No other exceptions handled yet. */
as_yet_unhandled:
csrr t0, mcause /* For viewing in the debugger only. */
j as_yet_unhandled
processed_source:
load_x t1, pxCurrentTCB /* Load pxCurrentTCB. */
load_x sp, 0( t1 ) /* Read sp from first TCB member. */
/* Load mret with the address of the next instruction in the task to run next. */
load_x t0, 0( sp )
csrw mepc, t0
portasmRESTORE_ADDITIONAL_REGISTERS /* Defined in freertos_risc_v_chip_specific_extensions.h to restore any registers unique to the RISC-V implementation. */
/* Load mstatus with the interrupt enable bits used by the task. */
load_x t0, 29 * portWORD_SIZE( sp )
csrw mstatus, t0 /* Required for MPIE bit. */
load_x x1, 1 * portWORD_SIZE( sp )
load_x x5, 2 * portWORD_SIZE( sp ) /* t0 */
load_x x6, 3 * portWORD_SIZE( sp ) /* t1 */
load_x x7, 4 * portWORD_SIZE( sp ) /* t2 */
load_x x8, 5 * portWORD_SIZE( sp ) /* s0/fp */
load_x x9, 6 * portWORD_SIZE( sp ) /* s1 */
load_x x10, 7 * portWORD_SIZE( sp ) /* a0 */
load_x x11, 8 * portWORD_SIZE( sp ) /* a1 */
load_x x12, 9 * portWORD_SIZE( sp ) /* a2 */
load_x x13, 10 * portWORD_SIZE( sp ) /* a3 */
load_x x14, 11 * portWORD_SIZE( sp ) /* a4 */
load_x x15, 12 * portWORD_SIZE( sp ) /* a5 */
load_x x16, 13 * portWORD_SIZE( sp ) /* a6 */
load_x x17, 14 * portWORD_SIZE( sp ) /* a7 */
load_x x18, 15 * portWORD_SIZE( sp ) /* s2 */
load_x x19, 16 * portWORD_SIZE( sp ) /* s3 */
load_x x20, 17 * portWORD_SIZE( sp ) /* s4 */
load_x x21, 18 * portWORD_SIZE( sp ) /* s5 */
load_x x22, 19 * portWORD_SIZE( sp ) /* s6 */
load_x x23, 20 * portWORD_SIZE( sp ) /* s7 */
load_x x24, 21 * portWORD_SIZE( sp ) /* s8 */
load_x x25, 22 * portWORD_SIZE( sp ) /* s9 */
load_x x26, 23 * portWORD_SIZE( sp ) /* s10 */
load_x x27, 24 * portWORD_SIZE( sp ) /* s11 */
load_x x28, 25 * portWORD_SIZE( sp ) /* t3 */
load_x x29, 26 * portWORD_SIZE( sp ) /* t4 */
load_x x30, 27 * portWORD_SIZE( sp ) /* t5 */
load_x x31, 28 * portWORD_SIZE( sp ) /* t6 */
addi sp, sp, portCONTEXT_SIZE
/* restore t0 and save sp in mscratch. */
csrr t0, mscratch
csrw mscratch, sp
/* Switch to ISR stack before function call. */
load_x sp, xISRStackTop
portSAVE_BaseReg
csrrw t0, mscratch, t0
/* SP = X2, so save it */
store_x t0, PORT_CONTEXT_xOFFSET(2)(sp)
/* Defined in freertos_risc_v_chip_specific_extensions.h to save any registers unique to the RISC-V implementation. */
portasmSAVE_ADDITIONAL_REGISTERS
/* Save any fpu registers */
portSAVE_FpuReg
/* Execption is treated by external function */
jal portHANDLE_EXCEPTION
/* in case that the go back from exception, restore registers */
portRESTORE_FpuReg
portasmRESTORE_ADDITIONAL_REGISTERS
portRESTORE_BaseReg
load_x x2, PORT_CONTEXT_xOFFSET(2)(sp)
mret
ecall_yield:
portSAVE_BaseReg
/* a4 = mepc
* a5 = mstatus
* s0 will be use for pxCurrentTCB
* s1 will be use to save sp
*/
/* Synchronous so updated exception return address to the instruction after the instruction that generated the exeption. */
addi t0, a4, 4
store_x t0, PORT_CONTEXT_mepcOFFSET(sp)
/* Store the value of sp when the interrupt occur */
addi t0, sp, portasmREGISTER_CONTEXT_WORDSIZE
store_x t0, PORT_CONTEXT_xOFFSET(2)(sp)
/* Defined in freertos_risc_v_chip_specific_extensions.h to save any registers unique to the RISC-V implementation. */
portasmSAVE_ADDITIONAL_REGISTERS
/* Save any fpu registers */
portSAVE_FpuReg
/* Load pxCurrentTCB and update first TCB member(pxTopOfStack) with sp. */
load_x s0, pxCurrentTCB
store_x sp, 0( s0 )
/* Save sp into s1 */
mv s1, sp
load_x sp, xISRStackTop /* Switch to ISR stack before function call. */
j switch_context
handle_interrupt:
portSAVE_BaseReg
/* a4 = mepc
* a5 = mstatus
* s0 will be use for pxCurrentTCB
* s1 will be use to save sp
*/
/* Store the value of sp when the interrupt occur */
addi t0, sp, portasmREGISTER_CONTEXT_WORDSIZE
store_x t0, PORT_CONTEXT_xOFFSET(2)(sp)
/* Defined in freertos_risc_v_chip_specific_extensions.h to save any registers unique to the RISC-V implementation. */
portasmSAVE_ADDITIONAL_REGISTERS
/* Save any fpu registers */
portSAVE_FpuReg
/* Load pxCurrentTCB and update first TCB member(pxTopOfStack) with sp. */
load_x s0, pxCurrentTCB
store_x sp, 0( s0 )
/* Save sp into s1 */
mv s1, sp
load_x sp, xISRStackTop /* Switch to ISR stack before function call. */
#if( portasmHAS_MTIME != 0 )
addi t0, x0, 1
slli t0, t0, __riscv_xlen - 1 /* LSB is already set, shift into MSB. Shift 31 on 32-bit or 63 on 64-bit cores. */
addi t1, t0, 7 /* 0x8000[]0007 == machine timer interrupt. */
csrr t2, mcause
bne t2, t1, test_if_external_interrupt
load_x t0, pullMachineTimerCompareRegister /* Load address of compare register into t0. */
load_x t1, pullNextTime /* Load the address of ullNextTime into t1. */
#if( __riscv_xlen == 32 )
/* Update the 64-bit mtimer compare match value in two 32-bit writes. */
lw a0, 0(t1) /* Load the low word of ullNextTime into a0. */
lw a1, 4(t1) /* Load the high word of ullNextTime into a1. */
li t2, -1
sw t2, 4(t0) /* Store low word of ullNextTime into compare register. */
sw a0, 0(t0) /* Store low word of ullNextTime into compare register. */
sw a1, 4(t0) /* Store high word of ullNextTime into compare register. */
lw t0, uxTimerIncrementsForOneTick /* Load the value of ullTimerIncrementForOneTick into t0 (could this be optimized by storing in an array next to pullNextTime?). */
add a2, t0, a0 /* Add the low word of ullNextTime to the timer increments for one tick (assumes timer increment for one tick fits in 32-bits). */
sltu t2, a2, a0 /* See if the sum of low words overflowed (what about the zero case?). */
add a3, a1, t2 /* Add overflow to high word of ullNextTime. */
sw a2, 0(t1) /* Store new low word of ullNextTime. */
sw a3, 4(t1) /* Store new high word of ullNextTime. */
#endif /* ( __riscv_xlen == 32 ) */
#if( __riscv_xlen == 64 )
/* Update the 64-bit mtimer compare match value. */
ld a0, 0(t1) /* Load ullNextTime into a0. */
sd a0, 0(t0) /* Store ullNextTime into compare register. */
ld t0, uxTimerIncrementsForOneTick /* Load the value of ullTimerIncrementForOneTick into t0 (could this be optimized by storing in an array next to pullNextTime?). */
add a2, t0, a0 /* Add ullNextTime to the timer increments for one tick. */
sd a2, 0(t1) /* Store ullNextTime. */
#endif /* ( __riscv_xlen == 64 ) */
jal xTaskIncrementTick
beqz a0, restore_before_exit /* Don't switch context if incrementing tick didn't unblock a task. */
j switch_context
restore_before_exit:
mv sp, s1
j end_trap_handler
test_if_external_interrupt: /* If there is a CLINT and the mtimer interrupt is not pending then check to see if an external interrupt is pending. */
addi t1, t1, 4 /* 0x80000007 + 4 = 0x8000000b == Machine external interrupt. */
csrr t2, mcause
bne t2, t1, unrecoverable_error /* Something as yet unhandled. */
j unrecoverable_error
#endif /* ( portasmHAS_MTIME != 0 ) */
external_interrupt:
/* Switch to ISR stack before function call. */
load_x sp, xISRStackTop
jal portHANDLE_INTERRUPT
mv sp, s1
j end_trap_handler
unrecoverable_error:
csrr t0, mcause /* For viewing in the debugger only. */
csrr t1, mepc /* For viewing in the debugger only. */
csrr t2, mstatus
wfi
j unrecoverable_error
switch_context:
jal vTaskSwitchContext
load_x s0, pxCurrentTCB /* Load pxCurrentTCB. */
load_x sp, 0( s0 ) /* Read sp from first TCB member. */
end_trap_handler:
load_x s0, pxCurrentTCB /* Load pxCurrentTCB. */
load_x t1, PORT_CONTEXT_xOFFSET(2)(sp)
store_x t1, 0( s0 ) /* Write sp saved value to first TCB member. */
/* restore registers */
portRESTORE_FpuReg
portasmRESTORE_ADDITIONAL_REGISTERS
portRESTORE_BaseReg
load_x x2, PORT_CONTEXT_xOFFSET(2)(sp)
mret
.endfunc
/*-----------------------------------------------------------*/
@ -304,49 +608,37 @@ xPortStartFirstTask:
outside of this file. */
la t0, freertos_risc_v_trap_handler
csrw mtvec, t0
#endif /* portasmHAS_CLILNT */
load_x sp, pxCurrentTCB /* Load pxCurrentTCB. */
load_x sp, 0( sp ) /* Read sp from first TCB member. */
load_x x1, 0( sp ) /* Note for starting the scheduler the exception return address is used as the function return address. */
portasmRESTORE_ADDITIONAL_REGISTERS /* Defined in freertos_risc_v_chip_specific_extensions.h to restore any registers unique to the RISC-V implementation. */
load_x x6, 3 * portWORD_SIZE( sp ) /* t1 */
load_x x7, 4 * portWORD_SIZE( sp ) /* t2 */
load_x x8, 5 * portWORD_SIZE( sp ) /* s0/fp */
load_x x9, 6 * portWORD_SIZE( sp ) /* s1 */
load_x x10, 7 * portWORD_SIZE( sp ) /* a0 */
load_x x11, 8 * portWORD_SIZE( sp ) /* a1 */
load_x x12, 9 * portWORD_SIZE( sp ) /* a2 */
load_x x13, 10 * portWORD_SIZE( sp ) /* a3 */
load_x x14, 11 * portWORD_SIZE( sp ) /* a4 */
load_x x15, 12 * portWORD_SIZE( sp ) /* a5 */
load_x x16, 13 * portWORD_SIZE( sp ) /* a6 */
load_x x17, 14 * portWORD_SIZE( sp ) /* a7 */
load_x x18, 15 * portWORD_SIZE( sp ) /* s2 */
load_x x19, 16 * portWORD_SIZE( sp ) /* s3 */
load_x x20, 17 * portWORD_SIZE( sp ) /* s4 */
load_x x21, 18 * portWORD_SIZE( sp ) /* s5 */
load_x x22, 19 * portWORD_SIZE( sp ) /* s6 */
load_x x23, 20 * portWORD_SIZE( sp ) /* s7 */
load_x x24, 21 * portWORD_SIZE( sp ) /* s8 */
load_x x25, 22 * portWORD_SIZE( sp ) /* s9 */
load_x x26, 23 * portWORD_SIZE( sp ) /* s10 */
load_x x27, 24 * portWORD_SIZE( sp ) /* s11 */
load_x x28, 25 * portWORD_SIZE( sp ) /* t3 */
load_x x29, 26 * portWORD_SIZE( sp ) /* t4 */
load_x x30, 27 * portWORD_SIZE( sp ) /* t5 */
load_x x31, 28 * portWORD_SIZE( sp ) /* t6 */
load_x x5, 29 * portWORD_SIZE( sp ) /* Initial mstatus into x5 (t0) */
addi x5, x5, 0x08 /* Set MIE bit so the first task starts with interrupts enabled - required as returns with ret not eret. */
csrrw x0, mstatus, x5 /* Interrupts enabled from here! */
load_x x5, 2 * portWORD_SIZE( sp ) /* Initial x5 (t0) value. */
addi sp, sp, portCONTEXT_SIZE
ret
#endif /* ( portasmHAS_SIFIVE_CLINT != 0 ) */
/** Set all register to the FirstTask context */
load_x t2, pxCurrentTCB /* Load pxCurrentTCB. */
load_x sp, 0( t2 ) /* Read sp from first TCB member. */
/* Restore first TCB member */
load_x t1, PORT_CONTEXT_xOFFSET(2)(sp)
store_x t1, 0( t2 ) /* Write sp saved value to first TCB member. */
/* enable interrupt */
#if( portasmHAS_MTIME != 0 )
li t0, 0x880
csrs mie, t0
#else
li t0, 0x800
csrs mie, t0
#endif /* ( portasmHAS_MTIME != 0 ) */
portRESTORE_FpuReg
portasmRESTORE_ADDITIONAL_REGISTERS
/* Set MIE bit so the first task starts with interrupts enabled - required as returns with ret not eret. */
load_x t1, PORT_CONTEXT_mstatusOFFSET(sp)
addi t1, t1, 0x08
store_x t1, PORT_CONTEXT_mstatusOFFSET(sp)
portRESTORE_BaseReg
load_x ra, PORT_CONTEXT_mepcOFFSET(sp) /* Note for starting the scheduler the exception return address is used as the function return address. */
load_x x2, PORT_CONTEXT_xOFFSET(2)(sp)
mret
.endfunc
/*-----------------------------------------------------------*/
@ -360,7 +652,7 @@ xPortStartFirstTask:
* a1, and pvParameters in a2. The new top of stack is passed out in a0.
*
* RISC-V maps registers to ABI names as follows (X1 to X31 integer registers
* for the 'I' profile, X1 to X15 for the 'E' profile, currently I assumed).
* for the 'I' profile, X1 to X15 for the 'E' profile).
*
* Register ABI Name Description Saver
* x0 zero Hard-wired zero -
@ -379,36 +671,44 @@ xPortStartFirstTask:
* The RISC-V context is saved t FreeRTOS tasks in the following stack frame,
* where the global and thread pointers are currently assumed to be constant so
* are not saved:
* The RISC-V context is saved t FreeRTOS tasks in the following stack frame:
*
* ruf (in order to be 16 bytes aligned)
* ruf (in order to be 16 bytes aligned)
* pxCode - mepc
* mstatus
* x31
* x30
* x29
* x28
* x27
* x26
* x25
* x24
* x23
* x22
* x21
* x20
* x19
* x18
* x17
* x16
* x31 (Only for 'I' profile)
* x30 (Only for 'I' profile)
* x29 (Only for 'I' profile)
* x28 (Only for 'I' profile)
* x27 (Only for 'I' profile)
* x26 (Only for 'I' profile)
* x25 (Only for 'I' profile)
* x24 (Only for 'I' profile)
* x23 (Only for 'I' profile)
* x22 (Only for 'I' profile)
* x21 (Only for 'I' profile)
* x20 (Only for 'I' profile)
* x19 (Only for 'I' profile)
* x18 (Only for 'I' profile)
* x17 (Only for 'I' profile)
* x16 (Only for 'I' profile)
* x15
* x14
* x13
* x12
* x11
* pvParameters
* pvParameters - x10 (a0)
* x9
* x8
* x7
* x6
* x5
* portTASK_RETURN_ADDRESS
* x4 (tp)
* x3 (gp)
* x2 (sp)
* portTASK_RETURN_ADDRESS - x1 (ra)
* x0
* [chip specific registers go here]
* pxCode
*/
@ -420,24 +720,75 @@ pxPortInitialiseStack:
andi t0, t0, ~0x8 /* Ensure interrupts are disabled when the stack is restored within an ISR. Required when a task is created after the schedulre has been started, otherwise interrupts would be disabled anyway. */
addi t1, x0, 0x188 /* Generate the value 0x1880, which are the MPIE and MPP bits to set in mstatus. */
slli t1, t1, 4
not t2, t1 /* reset previous value */
and t0, t0, t2
or t0, t0, t1 /* Set MPIE and MPP bits in mstatus value. */
addi a0, a0, -portWORD_SIZE
store_x t0, 0(a0) /* mstatus onto the stack. */
addi a0, a0, -(22 * portWORD_SIZE) /* Space for registers x11-x31. */
store_x a2, 0(a0) /* Task parameters (pvParameters parameter) goes into register X10/a0 on the stack. */
addi a0, a0, -(6 * portWORD_SIZE) /* Space for registers x5-x9. */
store_x x0, 0(a0) /* Return address onto the stack, could be portTASK_RETURN_ADDRESS */
addi t0, x0, portasmADDITIONAL_CONTEXT_SIZE /* The number of chip specific additional registers. */
/* Make room for the registers. */
addi t2, a0, -portasmREGISTER_CONTEXT_WORDSIZE
store_x x0, PORT_CONTEXT_xOFFSET(1)(t2) /* x1(ra) Return address */
store_x a0, PORT_CONTEXT_xOFFSET(2)(t2) /* x2(sp) Stack pointer */
store_x x3, PORT_CONTEXT_xOFFSET(3)(t2) /* x3(gp) Global pointer */
store_x x4, PORT_CONTEXT_xOFFSET(4)(t2) /* x4(tp) Thread pointer */
store_x x0, PORT_CONTEXT_xOFFSET(5)(t2) /* x5(t0) Temporaries */
store_x x0, PORT_CONTEXT_xOFFSET(6)(t2) /* x6(t1) Temporaries */
store_x x0, PORT_CONTEXT_xOFFSET(7)(t2) /* x7(t2) Temporaries */
store_x x0, PORT_CONTEXT_xOFFSET(8)(t2) /* x8(s0/fp) Saved register/Frame pointer */
store_x x0, PORT_CONTEXT_xOFFSET(9)(t2) /* x9(s1) Saved register */
store_x a2, PORT_CONTEXT_xOFFSET(10)(t2) /* x10(a0) Function arguments */
store_x x0, PORT_CONTEXT_xOFFSET(11)(t2) /* x11(a1) Function arguments */
store_x x0, PORT_CONTEXT_xOFFSET(12)(t2) /* x12(a2) Function arguments */
store_x x0, PORT_CONTEXT_xOFFSET(13)(t2) /* x13(a3) Function arguments */
store_x x0, PORT_CONTEXT_xOFFSET(14)(t2) /* x14(a4) Function arguments */
store_x x0, PORT_CONTEXT_xOFFSET(15)(t2) /* x15(a5) Function arguments */
#ifndef __riscv_32e
store_x x0, PORT_CONTEXT_xOFFSET(16)(t2) /* x16(a6) Function arguments */
store_x x0, PORT_CONTEXT_xOFFSET(17)(t2) /* x17(a7) Function arguments */
store_x x0, PORT_CONTEXT_xOFFSET(18)(t2) /* x18(s2) Saved registers */
store_x x0, PORT_CONTEXT_xOFFSET(19)(t2) /* x19(s3) Saved registers */
store_x x0, PORT_CONTEXT_xOFFSET(20)(t2) /* x20(s4) Saved registers */
store_x x0, PORT_CONTEXT_xOFFSET(21)(t2) /* x21(s5) Saved registers */
store_x x0, PORT_CONTEXT_xOFFSET(22)(t2) /* x22(s6) Saved registers */
store_x x0, PORT_CONTEXT_xOFFSET(23)(t2) /* x23(s7) Saved registers */
store_x x0, PORT_CONTEXT_xOFFSET(24)(t2) /* x24(s8) Saved registers */
store_x x0, PORT_CONTEXT_xOFFSET(25)(t2) /* x25(s9) Saved registers */
store_x x0, PORT_CONTEXT_xOFFSET(26)(t2) /* x26(s10) Saved registers */
store_x x0, PORT_CONTEXT_xOFFSET(27)(t2) /* x27(s11) Saved registers */
store_x x0, PORT_CONTEXT_xOFFSET(28)(t2) /* x28(t3) Temporaries */
store_x x0, PORT_CONTEXT_xOFFSET(29)(t2) /* x29(t4) Temporaries */
store_x x0, PORT_CONTEXT_xOFFSET(30)(t2) /* x30(t5) Temporaries */
store_x x0, PORT_CONTEXT_xOFFSET(31)(t2) /* x31(t6) Temporaries */
#endif /* __riscv_32e */
store_x a1, PORT_CONTEXT_mepcOFFSET(t2)
store_x t0, PORT_CONTEXT_mstatusOFFSET(t2)
/* The number of additional registers. */
addi t0, x0, portasmADDITIONAL_CONTEXT_SIZE
chip_specific_stack_frame: /* First add any chip specific registers to the stack frame being created. */
beq t0, x0, 1f /* No more chip specific registers to save. */
addi a0, a0, -portWORD_SIZE /* Make space for chip specific register. */
store_x x0, 0(a0) /* Give the chip specific register an initial value of zero. */
addi t2, t2, -portWORD_SIZE /* Make space for chip specific register. */
store_x x0, 0(t2) /* Give the chip specific register an initial value of zero. */
addi t0, t0, -1 /* Decrement the count of chip specific registers remaining. */
j chip_specific_stack_frame /* Until no more chip specific registers. */
1:
addi a0, a0, -portWORD_SIZE
store_x a1, 0(a0) /* mret value (pxCode parameter) onto the stack. */
#ifdef __riscv_fdiv
/* Make room for the fpu registers. */
/* Here we use the memory space needed for all fpu registers instead of using the number of fpu registers */
/* Thanks to it we usually manage any xxbits core with yybits fpu */
addi t0, x0, portasmFPU_CONTEXT_WORDSIZE
fpu_specific_stack_frame:
beq t0, x0, 1f /* No more space is needed. */
addi t2, t2, -portWORD_SIZE
store_x x0, 0(t2) /* Give an initial value of zero. */
addi t0, t0, -portWORD_SIZE /* Decrement the count space remaining. */
j fpu_specific_stack_frame /* Until no more space is needed. */
1:
#endif /* __riscv_fdiv */
mv a0, t2
ret
.endfunc
/*-----------------------------------------------------------*/

Write Preview
Loading…
Cancel
Save