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154 lines
3.4 KiB
ArmAsm
154 lines
3.4 KiB
ArmAsm
16 years ago
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/*
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* File: mcf5225x_lo.s
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* Purpose: Low-level routines for the MCF5225x.
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*
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* Notes:
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*
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* License: All software covered by license agreement in -
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* docs/Freescale_Software_License.pdf
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*/
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#define mcf5225x_init _mcf5225x_init
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#define common_startup _common_startup
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#define cpu_startup _cpu_startup
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#define main _main
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#define __IPSBAR ___IPSBAR
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#define __SRAM ___SRAM
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#define __FLASH ___FLASH
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#define __SP_INIT ___SP_INIT
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.extern __IPSBAR
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.extern __SRAM
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.extern __FLASH
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.extern __SP_INIT
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.extern mcf5225x_init
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.extern common_startup
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.extern cpu_startup
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.extern main
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.global asm_startmeup
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.global _asm_startmeup
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.global d0_reset
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.global _d0_reset
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.global d1_reset
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.global _d1_reset
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.data
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d0_reset:
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_d0_reset: .long 0
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d1_reset:
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_d1_reset: .long 0
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.text
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/********************************************************************
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*
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* This is the main entry point upon hard reset. The memory map is
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* setup based on linker file definitions, then the higher level
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* system initialization routine is called. Finally, we jump to the
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* "main" process.
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*/
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asm_startmeup:
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_asm_startmeup:
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move.w #0x2700,sr
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/* Save off reset values of D0 and D1 */
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move.l d0,d6
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move.l d1,d7
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/* Initialize RAMBAR1: locate SRAM and validate it */
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move.l #__SRAM,d0
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andi.l #0xFFFF0000,d0
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add.l #0x21,d0
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movec d0,RAMBAR1
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/* Locate Stack Pointer */
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move.l #__SP_INIT,sp
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/* Initialize IPSBAR */
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move.l #__IPSBAR,d0
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add.l #0x1,d0
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move.l d0,0x40000000
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/* Initialize FLASHBAR */
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move.l #__FLASH,d0
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cmp.l #0x00000000,d0
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bne change_flashbar
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add.l #0x61,d0
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movec d0,RAMBAR0
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_continue_startup:
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/* Locate Stack Pointer */
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move.l #__SP_INIT,sp
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/* Initialize the system */
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jsr mcf5225x_init
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/* Common startup code */
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//jsr common_startup
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/* Save off intial D0 and D1 to RAM */
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move.l d6,d0_reset
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move.l d7,d1_reset
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/* CPU specific startup code */
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//jsr cpu_startup
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/* Jump to the main process */
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jsr main
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bra .
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nop
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nop
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halt
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change_flashbar:
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/*
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* The following sequence is used to set FLASHBAR. Since we may
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* be executing from Flash, we must put the routine into SRAM for
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* execution and then jump back to Flash using the new address.
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*
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* The following instructions are coded into the SRAM:
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*
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* move.l #(__FLASH + 0x21),d0
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* movec d0, RAMBAR0
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* jmp _continue_startup
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*
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* An arbitrary SRAM address is chosen until the real address
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* can be loaded.
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*
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* This routine is not necessary if the default Flash address
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* (0x00000000) is used.
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*
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* If running in SRAM, change_flashbar should not be executed
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*/
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move.l #__SRAM,a0
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/* Code "move.l #(__FLASH + 0x21),d0" into SRAM */
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move.w #0x203C,d0
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move.w d0,(a0)+
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move.l #__FLASH,d0
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add.l #0x21,d0
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move.l d0,(a0)+
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/* Code "movec d0,FLASHBAR" into SRAM */
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move.l #0x4e7b0C04,d0
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move.l d0,(a0)+
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/* Code "jmp _continue_startup" into SRAM */
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move.w #0x4EF9,d0
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move.w d0,(a0)+
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move.l #_continue_startup,d0
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move.l d0,(a0)+
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/* Jump to code segment in internal SRAM */
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jmp __SRAM
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/********************************************************************/
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.end
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