92 lines
4.3 KiB
Plaintext
92 lines
4.3 KiB
Plaintext
1 ; crt0.s for Colecovision cart
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2
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3 .module crt0
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4 .globl _main
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5 .globl _cv_init
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6 .globl _cv_spint_handler
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7 .globl _cv_vint
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8 .globl _cv_start
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9 .globl ___sdcc_call_hl
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10
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11 ; Ordering of segments for the linker - copied from sdcc crt0.s
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12 .area _CODE
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13 .area _INITIALIZER
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14 .area _HOME
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15 .area _GSINIT
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16 .area _GSFINAL
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17 .area _DATA
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18 .area _INITIALIZED
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19 .area _BSEG
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20 .area _BSS
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21 .area _HEAP
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22
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23 .area _CODE
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24 ; MSX cartridge header @ 0x4000 - 0x400f
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0000 41 42 25 .dw 0x4241
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0002r10r00 26 .dw _cv_start
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0004r10r00 27 .dw _cv_start
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0006 00 00 28 .dw 0
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0008 00 00 29 .dw 0
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000A 00 00 30 .dw 0
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000C 00 00 31 .dw 0
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000E 00 00 32 .dw 0
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33
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0010 34 _cv_start:
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0010 F3 [ 4] 35 di
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0011 31 00 E0 [10] 36 ld sp, #0xe000 ; Set stack pointer directly above top of memory.
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0014 ED 56 [ 8] 37 im 1
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38
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0016 CDr00r00 [17] 39 call gsinit ; Initialize global and static variables.
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0019 CDr00r00 [17] 40 call vinthook
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001C CDr00r00 [17] 41 call _cv_init ; Initialize Colecovision specific stuff.
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001F CDr00r00 [17] 42 call _main
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0022 C7 [11] 43 rst 0x0 ; Restart when main() returns.
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44
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45 .area _GSINIT
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0000 46 gsinit::
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47
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48 ; Implicitly zeroed global and static variables.
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0000 01r00r00 [10] 49 ld bc, #l__DATA
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0003 78 [ 4] 50 ld a, b
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0004 B1 [ 4] 51 or a, c
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0005 28 0F [12] 52 jr Z, zeroed_data
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0007 21r00r00 [10] 53 ld hl, #s__DATA
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000A 36 00 [10] 54 ld (hl), #0x00
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000C 0B [ 6] 55 dec bc
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000D 78 [ 4] 56 ld a, b
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000E B1 [ 4] 57 or a, c
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000F 28 05 [12] 58 jr Z, zeroed_data
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0011 5D [ 4] 59 ld e, l
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0012 54 [ 4] 60 ld d, h
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0013 13 [ 6] 61 inc de
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0014 ED B0 [21] 62 ldir
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0016 63 zeroed_data:
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64
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65 ; Explicitly initialized global variables.
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0016 01r00r00 [10] 66 ld bc, #l__INITIALIZER
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0019 78 [ 4] 67 ld a, b
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001A B1 [ 4] 68 or a, c
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001B 28 08 [12] 69 jr Z, gsinit_static
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001D 11r00r00 [10] 70 ld de, #s__INITIALIZED
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0020 21r00r00 [10] 71 ld hl, #s__INITIALIZER
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0023 ED B0 [21] 72 ldir
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73
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0025 74 gsinit_static:
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75 ; Explicitly initialized static variables inserted by compiler here.
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76
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77 .area _GSFINAL
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0000 C9 [10] 78 ret
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79
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80 .area _HOME
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81
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82 ; set up timer hook
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FD9F 83 H_TIMI = 0xFD9F
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0000 84 vinthook:
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0000 3E C3 [ 7] 85 ld a,#0xc3
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0002 32 9F FD [13] 86 ld (H_TIMI),a
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0005 3Er00 [ 7] 87 ld a, #<(_cv_vint)
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0007 32 A0 FD [13] 88 ld (H_TIMI+1),a
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000A 3Es00 [ 7] 89 ld a, #>(_cv_vint)
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000C 32 A1 FD [13] 90 ld (H_TIMI+2),a
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000F C9 [10] 91 ret
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