各位老大 小弟我不太会用汇编 请多多指教 谢谢
init.s
GET memory.a
GET snds.a
AREA Init, CODE, READONLY
; --- Define entry point
EXPORT __main ; defined to ensure that C runtime system
__main ; is not linked in
ENTRY
; --- Setup interrupt / exception vectors
IF :DEF: ROM_AT_ADDRESS_ZERO
; If the ROM is at address 0 this is just a sequence of branches
B Reset_Handler
B Undefined_Handler
B SWI_Handler
B Prefetch_Handler
B Abort_Handler
NOP ; Reserved vector
B IRQ_Handler
B FIQ_Handler
ELSE
; Otherwise we copy a sequence of LDR PC instructions over the vectors
; (Note: We copy LDR PC instructions because branch instructions
; could not simply be copied, the offset in the branch instruction
; would have to be modified so that it branched into ROM. Also, a
; branch instructions might not reach if the ROM is at an address
; > 32M).
MOV R8, #0
ADR R9, Vector_Init_Block
LDMIA R9!, {R0-R7}
STMIA R8!, {R0-R7}
LDMIA R9!, {R0-R7}
STMIA R8!, {R0-R7}
; Now fall into the LDR PC, Reset_Addr instruction which will continue
; execution at 'Reset_Handler'
Vector_Init_Block
LDR PC, Reset_Addr
LDR PC, Undefined_Addr
LDR PC, SWI_Addr
LDR PC, Prefetch_Addr
LDR PC, Abort_Addr
NOP
LDR PC, IRQ_Addr
LDR PC, FIQ_Addr
Reset_Addr DCD Reset_Handler
Undefined_Addr DCD Undefined_Handler
SWI_Addr DCD SWI_Handler
Prefetch_Addr DCD Prefetch_Handler
Abort_Addr DCD Abort_Handler
DCD 0 ; Reserved vector
IRQ_Addr DCD IRQ_Handler
FIQ_Addr DCD FIQ_Handler
ENDIF
;==========================================================
; The Default Exception Handler Vector Entry Pointer Setup
;==========================================================
FIQ_Handler
SUB sp, sp, #4
STMFD sp!, {r0}
LDR r0, =HandleFiq
LDR r0, [r0]
STR r0, [sp, #4]
LDMFD sp!, {r0, pc}
IRQ_Handler
SUB sp, sp, #4
STMFD sp!, {r0}
LDR r0, =HandleIrq
LDR r0, [r0]
STR r0, [sp, #4]
LDMFD sp!, {r0, pc}
Prefetch_Handler
SUB sp, sp, #4
STMFD sp!, {r0}
LDR r0, =HandlePrefetch
LDR r0, [r0]
STR r0, [sp, #4]
LDMFD sp!, {r0, pc}
Abort_Handler
SUB sp, sp, #4
STMFD sp!, {r0}
LDR r0, =HandleAbort
LDR r0, [r0]
STR r0, [sp, #4]
LDMFD sp!, {r0, pc}
Undefined_Handler
SUB sp, sp, #4
STMFD sp!, {r0}
LDR r0, =HandleUndef
LDR r0, [r0]
STR r0, [sp, #4]
LDMFD sp!, {r0, pc}
SWI_Handler
SUB sp, sp, #4
STMFD sp!, {r0}
LDR r0, =HandleSwi
LDR r0, [r0]
STR r0, [sp, #4]
LDMFD sp!, {r0, pc}
AREA Main, CODE, READONLY
;==========================================================
; The Reset Entry Point
;==========================================================
EXPORT Reset_Handler
Reset_Handler ;/* Reset Entry Point */
LDR r1, =IntMask
LDR r0, =0xFFFFFFFF
STR r0, [r1]
[ ROM_AT_ADDRESS_ZERO /*151行错误*/
LDR r0, =HandleSwi ; SWI exception table address
LDR r1, =SystemSwiHandler
STR r1, ][r0]
swi 0xff ;/* Call SWI Vector */
]
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