2018-03-14 20:14:02 +00:00
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.macro CLEAR_GPR_REG_ITER
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mov r\@, #0
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.endm
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.section .text.start
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.arm
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.align 5
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.global _start
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_start:
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2018-03-15 22:12:38 +00:00
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/* Insert NOPs for convenience (i.e. to use Nintendo's BCTs, for example) */
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.rept 16
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nop
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.endr
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2018-03-14 20:14:02 +00:00
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/* Switch to supervisor mode, mask all interrupts, clear all flags */
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msr cpsr_cxsf, #0xDF
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/* Relocate ourselves if necessary */
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2018-04-08 11:06:04 +00:00
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ldr r2, =__start__
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adr r3, _start
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cmp r2, r3
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2018-03-14 20:14:02 +00:00
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bne _relocation_loop_end
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2018-04-08 11:06:04 +00:00
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ldr r4, =__bss_start__
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sub r4, r4, r2 /* size >= 32, obviously */
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2018-03-14 20:14:02 +00:00
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_relocation_loop:
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2018-04-08 11:06:04 +00:00
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ldmia r3!, {r5-r12}
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stmia r2!, {r5-r12}
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subs r4, #0x20
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2018-03-14 20:14:02 +00:00
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bne _relocation_loop
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ldr r12, =_relocation_loop_end
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bx r12
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_relocation_loop_end:
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/* Set the stack pointer */
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ldr sp, =0x40008000
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mov fp, #0
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2018-04-08 11:06:04 +00:00
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stmfd sp!, {r0, r1}
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2018-03-14 20:14:02 +00:00
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/* Clear .bss */
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ldr r0, =__bss_start__
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mov r1, #0
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ldr r2, =__bss_end__
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sub r2, r2, r0
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bl memset
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/* Call global constructors */
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bl __libc_init_array
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/* Set r0 to r12 to 0 (because why not?) & call main */
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.rept 13
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CLEAR_GPR_REG_ITER
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.endr
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2018-04-08 11:06:04 +00:00
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ldmfd sp!, {r0, r1}
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2018-03-14 20:14:02 +00:00
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bl main
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b .
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