diff options
Diffstat (limited to 'gba/start')
| -rw-r--r-- | gba/start/pkjb_crt0.s | 102 |
1 files changed, 102 insertions, 0 deletions
| diff --git a/gba/start/pkjb_crt0.s b/gba/start/pkjb_crt0.s new file mode 100644 index 0000000..0d9d657 --- /dev/null +++ b/gba/start/pkjb_crt0.s | |||
| @@ -0,0 +1,102 @@ | |||
| 1 | .section ".init" | ||
| 2 | .global _start | ||
| 3 | .align | ||
| 4 | .arm | ||
| 5 | @--------------------------------------------------------------------------------- | ||
| 6 | _start: | ||
| 7 | @--------------------------------------------------------------------------------- | ||
| 8 | b rom_header_end | ||
| 9 | |||
| 10 | .fill 156,1,0 @ Nintendo Logo Character Data (8000004h) | ||
| 11 | .fill 16,1,0 @ Game Title | ||
| 12 | .byte 0x30,0x31 @ Maker Code (80000B0h) | ||
| 13 | .byte 0x96 @ Fixed Value (80000B2h) | ||
| 14 | .byte 0x00 @ Main Unit Code (80000B3h) | ||
| 15 | .byte 0x00 @ Device Type (80000B4h) | ||
| 16 | .fill 7,1,0 @ unused | ||
| 17 | .byte 0x00 @ Software Version No (80000BCh) | ||
| 18 | .byte 0xf0 @ Complement Check (80000BDh) | ||
| 19 | .byte 0x00,0x00 @ Checksum (80000BEh) | ||
| 20 | |||
| 21 | @--------------------------------------------------------------------------------- | ||
| 22 | rom_header_end: | ||
| 23 | @--------------------------------------------------------------------------------- | ||
| 24 | b start_vector @ This branch must be here for proper | ||
| 25 | @ positioning of the following header. | ||
| 26 | |||
| 27 | .GLOBAL __boot_method, __slave_number | ||
| 28 | @--------------------------------------------------------------------------------- | ||
| 29 | __boot_method: | ||
| 30 | @--------------------------------------------------------------------------------- | ||
| 31 | .byte 0 @ boot method (0=ROM boot, 3=Multiplay boot) | ||
| 32 | @--------------------------------------------------------------------------------- | ||
| 33 | __slave_number: | ||
| 34 | @--------------------------------------------------------------------------------- | ||
| 35 | .byte 0 @ slave # (1=slave#1, 2=slave#2, 3=slave#3) | ||
| 36 | |||
| 37 | .byte 0 @ reserved | ||
| 38 | .byte 0 @ reserved | ||
| 39 | .word 0 @ reserved | ||
| 40 | .word 0 @ reserved | ||
| 41 | .word 0 @ reserved | ||
| 42 | .word 0 @ reserved | ||
| 43 | .word 0 @ reserved | ||
| 44 | .word 0 @ reserved | ||
| 45 | |||
| 46 | .fill 4096,1,0 @ 4kb of filler so no useful code gets overwritten when flash bytes get copied over the top. | ||
| 47 | .global start_vector | ||
| 48 | .align | ||
| 49 | @--------------------------------------------------------------------------------- | ||
| 50 | start_vector: | ||
| 51 | @--------------------------------------------------------------------------------- | ||
| 52 | |||
| 53 | @--------------------------------------------------------------------------------- | ||
| 54 | @ Enter Thumb mode | ||
| 55 | @--------------------------------------------------------------------------------- | ||
| 56 | add r0, pc, #1 | ||
| 57 | bx r0 | ||
| 58 | |||
| 59 | .thumb | ||
| 60 | @ Turn off sound | ||
| 61 | ldr r1, =0x4000084 | ||
| 62 | eor r0, r0, r0 | ||
| 63 | strh r0, [r1] | ||
| 64 | |||
| 65 | @--------------------------------------------------------------------------------- | ||
| 66 | @ set heap end | ||
| 67 | @--------------------------------------------------------------------------------- | ||
| 68 | ldr r1, =fake_heap_end | ||
| 69 | ldr r0, =__eheap_end | ||
| 70 | str r0, [r1] | ||
| 71 | @--------------------------------------------------------------------------------- | ||
| 72 | @ global constructors | ||
| 73 | @--------------------------------------------------------------------------------- | ||
| 74 | ldr r3, =__libc_init_array | ||
| 75 | push {lr} | ||
| 76 | bl _blx_r3_stub | ||
| 77 | @--------------------------------------------------------------------------------- | ||
| 78 | @ Jump to user code | ||
| 79 | @--------------------------------------------------------------------------------- | ||
| 80 | mov r0, #0 @ int argc | ||
| 81 | mov r1, #0 @ char *argv[] | ||
| 82 | ldr r3, =main | ||
| 83 | bl _blx_r3_stub | ||
| 84 | @; If we're here, turn the sound back on before we return | ||
| 85 | ldr r1, =0x4000084 | ||
| 86 | mov r0, #0x8F | ||
| 87 | strh r0, [r1] | ||
| 88 | @; Also turn interrupts back on | ||
| 89 | ldr r1, =0x4000208 | ||
| 90 | mov r0, #1 | ||
| 91 | str r0, [r1] | ||
| 92 | pop {pc} | ||
| 93 | |||
| 94 | @--------------------------------------------------------------------------------- | ||
| 95 | _blx_r3_stub: | ||
| 96 | @--------------------------------------------------------------------------------- | ||
| 97 | bx r3 | ||
| 98 | |||
| 99 | .align | ||
| 100 | .pool | ||
| 101 | .end | ||
| 102 | |||