Add optional FPU support to the MicroBlaze code.

Rearrange the order in which registers are saved to the stack in an interrupt to make it more logical, and introduce #defines for the offset from the stack pointer for each variable.
14 years ago · c9b5f43d11
parent 4d287dd1bf
commit c9b5f43d11
2 changed files with 161 additions and 103 deletions
--- a/Demo/MicroBlaze_Spartan-6_EthernetLite/SDKProjects/RTOSDemoSource/FreeRTOS_Source/portable/GCC/MicroBlaze/port.c
+++ b/Demo/MicroBlaze_Spartan-6_EthernetLite/SDKProjects/RTOSDemoSource/FreeRTOS_Source/portable/GCC/MicroBlaze/port.c
@ -64,6 +64,7 @@
 #include <string.h>

 /* Hardware includes. */
+#include <xparameters.h>
 #include <xintc.h>
 #include <xintc_i.h>
 #include <xtmrctr.h>
@ -78,6 +79,7 @@ to reach zero, so it is initialised to a high value. */
 /* The bit within the MSR register that enabled/disables interrupts. */
 #define portMSR_IE					( 0x02U )

+#define portINITIAL_FSR				( 0U )
 /*-----------------------------------------------------------*/

 /*
@ -138,6 +140,18 @@ const unsigned long ulR13 = ( unsigned long ) &_SDA_BASE_;
 	*pxTopOfStack = ( portSTACK_TYPE ) 0x00000000;
 	pxTopOfStack--;

+	#if XPAR_MICROBLAZE_0_USE_FPU == 1
+		/* The FSR value placed in the initial task context is just 0. */
+		*pxTopOfStack = portINITIAL_FSR;
+		pxTopOfStack--;
+	#endif
+
+	/* The MSR value placed in the initial task context should have interrupts
+	disabled.  Each task will enable interrupts automatically when it enters
+	the running state for the first time. */
+	*pxTopOfStack = mfmsr() & ~portMSR_IE;
+	pxTopOfStack--;
+
 	/* First stack an initial value for the critical section nesting.  This
 	is initialised to zero. */
 	*pxTopOfStack = ( portSTACK_TYPE ) 0x00;
@ -205,13 +219,6 @@ const unsigned long ulR13 = ( unsigned long ) &_SDA_BASE_;
 	pxTopOfStack--;
 	*pxTopOfStack = ( portSTACK_TYPE ) 0x1e;	/* R30 - must be saved across function calls. Callee-save. */
 	pxTopOfStack--;
-
-	/* The MSR is stacked between R30 and R31.  This should have interrupts
-	disabled.  Each task will enable interrupts automatically when it enters
-	the running state for the first time. */
-	*pxTopOfStack = mfmsr() & ~portMSR_IE;
-	pxTopOfStack--;
-
 	*pxTopOfStack = ( portSTACK_TYPE ) 0x1f;	/* R31 - must be saved across function calls. Callee-save. */
 	pxTopOfStack--;

@ -230,12 +237,8 @@ extern unsigned long _stack[];
 	this function is called. */
 	vApplicationSetupTimerInterrupt();

-	/* Reuse the stack from main as the stack for the interrupts/exceptions.
-	The value is adjusted slightly to allow functions called from the
-	interrupts/exceptions to write back into the stack of the interrupt/
-	exception function itself. */
+	/* Reuse the stack from main as the stack for the interrupts/exceptions. */
 	pulISRStack = ( unsigned long * ) _stack;
-	pulISRStack -= 2;

 	/* Restore the context of the first task that is going to run.  From here
 	on, the created tasks will be executing. */
--- a/Demo/MicroBlaze_Spartan-6_EthernetLite/SDKProjects/RTOSDemoSource/FreeRTOS_Source/portable/GCC/MicroBlaze/portasm.S
+++ b/Demo/MicroBlaze_Spartan-6_EthernetLite/SDKProjects/RTOSDemoSource/FreeRTOS_Source/portable/GCC/MicroBlaze/portasm.S
@ -58,6 +58,50 @@
 */

 #include "FreeRTOSConfig.h"
+#include "xparameters.h"
+
+/* The context is oversized to allow functions called from the ISR to write
+back into the caller stack. */
+#if XPAR_MICROBLAZE_0_USE_FPU == 1
+	#define portCONTEXT_SIZE 136
+#else
+	#define portCONTEXT_SIZE 132
+#endif
+
+/* Offsets from the stack pointer at which saved registers are placed. */
+#define portR31_OFFSET	4
+#define portR30_OFFSET	8
+#define portR29_OFFSET	12
+#define portR28_OFFSET	16
+#define portR27_OFFSET	20
+#define portR26_OFFSET	24
+#define portR25_OFFSET	28
+#define portR24_OFFSET	32
+#define portR23_OFFSET	36
+#define portR22_OFFSET	40
+#define portR21_OFFSET	44
+#define portR20_OFFSET	48
+#define portR19_OFFSET	52
+#define portR18_OFFSET	56
+#define portR17_OFFSET	60
+#define portR16_OFFSET	64
+#define portR15_OFFSET	68
+#define portR14_OFFSET	72
+#define portR13_OFFSET	76
+#define portR12_OFFSET	80
+#define portR11_OFFSET	84
+#define portR10_OFFSET	88
+#define portR9_OFFSET	92
+#define portR8_OFFSET	96
+#define portR7_OFFSET	100
+#define portR6_OFFSET	104
+#define portR5_OFFSET	108
+#define portR4_OFFSET	112
+#define portR3_OFFSET	116
+#define portR2_OFFSET	120
+#define portCRITICAL_NESTING_OFFSET 124
+#define portMSR_OFFSET 128
+#define portFSR_OFFSET 132

 	.extern pxCurrentTCB
 	.extern XIntc_DeviceInterruptHandler
@ -73,47 +117,53 @@
 .macro portSAVE_CONTEXT

 	/* Make room for the context on the stack. */
-	addik r1, r1, -132
-
-	/* Save r31 so it can then be used as a temporary. */
-	swi r31, r1, 4
-
-	/* Copy the msr into r31 - this is stacked later. */
-	mfs r31, rmsr
+	addik r1, r1, -portCONTEXT_SIZE

 	/* Stack general registers. */
-	swi r30, r1, 12
-	swi r29, r1, 16
-	swi r28, r1, 20
-	swi r27, r1, 24
-	swi r26, r1, 28
-	swi r25, r1, 32
-	swi r24, r1, 36
-	swi r23, r1, 40
-	swi r22, r1, 44
-	swi r21, r1, 48
-	swi r20, r1, 52
-	swi r19, r1, 56
-	swi r18, r1, 60
-	swi r17, r1, 64
-	swi r16, r1, 68
-	swi r15, r1, 72
-	swi r13, r1, 80
-	swi r12, r1, 84
-	swi r11, r1, 88
-	swi r10, r1, 92
-	swi r9, r1, 96
-	swi r8, r1, 100
-	swi r7, r1, 104
-	swi r6, r1, 108
-	swi r5, r1, 112
-	swi r4, r1, 116
-	swi r3, r1, 120
-	swi r2, r1, 124
+	swi r31, r1, portR31_OFFSET
+	swi r30, r1, portR30_OFFSET
+	swi r29, r1, portR29_OFFSET
+	swi r28, r1, portR28_OFFSET
+	swi r27, r1, portR27_OFFSET
+	swi r26, r1, portR26_OFFSET
+	swi r25, r1, portR25_OFFSET
+	swi r24, r1, portR24_OFFSET
+	swi r23, r1, portR23_OFFSET
+	swi r22, r1, portR22_OFFSET
+	swi r21, r1, portR21_OFFSET
+	swi r20, r1, portR20_OFFSET
+	swi r19, r1, portR19_OFFSET
+	swi r18, r1, portR18_OFFSET
+	swi r17, r1, portR17_OFFSET
+	swi r16, r1, portR16_OFFSET
+	swi r15, r1, portR15_OFFSET
+	/* R14 is saved later as it needs adjustment if a yield is performed. */
+	swi r13, r1, portR13_OFFSET
+	swi r12, r1, portR12_OFFSET
+	swi r11, r1, portR11_OFFSET
+	swi r10, r1, portR10_OFFSET
+	swi r9, r1, portR9_OFFSET
+	swi r8, r1, portR8_OFFSET
+	swi r7, r1, portR7_OFFSET
+	swi r6, r1, portR6_OFFSET
+	swi r5, r1, portR5_OFFSET
+	swi r4, r1, portR4_OFFSET
+	swi r3, r1, portR3_OFFSET
+	swi r2, r1, portR2_OFFSET

 	/* Stack the critical section nesting value. */
-	lwi r3, r0, uxCriticalNesting
-	swi r3, r1, 128
+	lwi r18, r0, uxCriticalNesting
+	swi r18, r1, portCRITICAL_NESTING_OFFSET
+
+	/* Stack MSR. */
+	mfs r18, rmsr
+	swi r18, r1, portMSR_OFFSET
+
+	#if XPAR_MICROBLAZE_0_USE_FPU == 1
+		/* Stack FSR. */
+		mfs r18, rfsr
+		swi r18, r1, portFSR_OFFSET
+	#endif

 	/* Save the top of stack value to the TCB. */
 	lwi r3, r0, pxCurrentTCB
@ -124,60 +174,66 @@
 .macro portRESTORE_CONTEXT

 	/* Load the top of stack value from the TCB. */
-	lwi r3, r0, pxCurrentTCB
-	lw	r1, r0, r3	
+	lwi r18, r0, pxCurrentTCB
+	lw	r1, r0, r18

 	/* Restore the general registers. */
-	lwi r31, r1, 4		
-	lwi r30, r1, 12		
-	lwi r29, r1, 16	
-	lwi r28, r1, 20	
-	lwi r27, r1, 24	
-	lwi r26, r1, 28	
-	lwi r25, r1, 32	
-	lwi r24, r1, 36	
-	lwi r23, r1, 40	
-	lwi r22, r1, 44	
-	lwi r21, r1, 48	
-	lwi r20, r1, 52	
-	lwi r19, r1, 56	
-	lwi r18, r1, 60	
-	lwi r17, r1, 64	
-	lwi r16, r1, 68	
-	lwi r15, r1, 72	
-	lwi r14, r1, 76	
-	lwi r13, r1, 80	
-	lwi r12, r1, 84	
-	lwi r11, r1, 88	
-	lwi r10, r1, 92	
-	lwi r9, r1, 96	
-	lwi r8, r1, 100	
-	lwi r7, r1, 104
-	lwi r6, r1, 108
-	lwi r5, r1, 112
-	lwi r4, r1, 116
-	lwi r2, r1, 124
+	lwi r31, r1, portR31_OFFSET
+	lwi r30, r1, portR30_OFFSET
+	lwi r29, r1, portR29_OFFSET
+	lwi r28, r1, portR28_OFFSET
+	lwi r27, r1, portR27_OFFSET
+	lwi r26, r1, portR26_OFFSET
+	lwi r25, r1, portR25_OFFSET
+	lwi r24, r1, portR24_OFFSET
+	lwi r23, r1, portR23_OFFSET
+	lwi r22, r1, portR22_OFFSET
+	lwi r21, r1, portR21_OFFSET
+	lwi r20, r1, portR20_OFFSET
+	lwi r19, r1, portR19_OFFSET
+	lwi r17, r1, portR17_OFFSET
+	lwi r16, r1, portR16_OFFSET
+	lwi r15, r1, portR15_OFFSET
+	lwi r14, r1, portR14_OFFSET
+	lwi r13, r1, portR13_OFFSET
+	lwi r12, r1, portR12_OFFSET
+	lwi r11, r1, portR11_OFFSET
+	lwi r10, r1, portR10_OFFSET
+	lwi r9, r1, portR9_OFFSET
+	lwi r8, r1, portR8_OFFSET
+	lwi r7, r1, portR7_OFFSET
+	lwi r6, r1, portR6_OFFSET
+	lwi r5, r1, portR5_OFFSET
+	lwi r4, r1, portR4_OFFSET
+	lwi r3, r1, portR3_OFFSET
+	lwi r2, r1, portR2_OFFSET

 	/* Reload the rmsr from the stack. */
-	lwi r3, r1, 8
-	mts rmsr, r3
+	lwi r18, r1, portMSR_OFFSET
+	mts rmsr, r18
+
+	#if XPAR_MICROBLAZE_0_USE_FPU == 1
+		/* Reload the FSR from the stack. */
+		lwi r18, r1, portFSR_OFFSET
+		mts rfsr, r18
+	#endif

 	/* Load the critical nesting value. */
-	lwi r3, r1, 128
-	swi r3, r0, uxCriticalNesting
+	lwi r18, r1, portCRITICAL_NESTING_OFFSET
+	swi r18, r0, uxCriticalNesting

 	/* Test the critical nesting value.  If it is non zero then the task last
 	exited the running state using a yield.  If it is zero, then the task
 	last exited the running state through an interrupt. */
-	xori r3, r3, 0
-	bnei r3, exit_from_yield
+	xori r18, r18, 0
+	bnei r18, exit_from_yield

-	/* r3 was being used as a temporary.  Now restore its true value from the
+	/* r18 was being used as a temporary.  Now restore its true value from the
 	stack. */
-	lwi r3, r1, 120
+	lwi r18, r1, portR18_OFFSET

 	/* Remove the stack frame. */
-	addik r1, r1, 132
+	addik r1, r1, portCONTEXT_SIZE

 	/* Return using rtid so interrupts are re-enabled as this function is
 	exited. */
@ -186,35 +242,33 @@

 	.endm

-	.text
-	.align  2
-
 /* This function is used to exit portRESTORE_CONTEXT() if the task being
 returned to last left the Running state by calling taskYIELD() (rather than
 being preempted by an interrupt. */
+	.text
+	.align  2
 exit_from_yield:

-	/* r3 was being used as a temporary.  Now restore its true value from the
+	/* r18 was being used as a temporary.  Now restore its true value from the
 	stack. */
-	lwi r3, r1, 120
+	lwi r18, r1, portR18_OFFSET

 	/* Remove the stack frame. */
-	addik r1, r1, 132
+	addik r1, r1, portCONTEXT_SIZE

 	/* Return to the task. */
 	rtsd r14, 0
 	or r0, r0, r0


+	.text
+	.align  2
 _interrupt_handler:

 	portSAVE_CONTEXT

-	/* Stack msr. */
-	swi r31, r1, 8
-
 	/* Stack the return address. */
-	swi r14, r1, 76
+	swi r14, r1, portR14_OFFSET

 	/* Switch to the ISR stack.  The pulISRStack value has already been set to
 	leave space for the caller function to write back into the stack of this
@ -232,17 +286,16 @@ _interrupt_handler:
 	portRESTORE_CONTEXT


+	.text
+	.align  2
 VPortYieldASM:

 	portSAVE_CONTEXT

-	/* Stack msr. */
-	swi r31, r1, 8
-
 	/* Modify the return address so a return is done to the instruction after
 	the call to VPortYieldASM. */
 	addi r14, r14, 8
-	swi r14, r1, 76
+	swi r14, r1, portR14_OFFSET

 	/* Switch to use the ISR stack. */
 	lwi r1, r0, pulISRStack
@ -254,6 +307,8 @@ VPortYieldASM:
 	/* Restore the context of the next task scheduled to execute. */
 	portRESTORE_CONTEXT

+	.text
+	.align  2
 vPortStartFirstTask:

 	portRESTORE_CONTEXT