mirror of https://github.com/pret/pokecrystal.git
135 lines
2.0 KiB
NASM
135 lines
2.0 KiB
NASM
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CopyBytes: ; 0x3026
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; copy bc bytes from hl to de
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inc b ; we bail the moment b hits 0, so include the last run
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inc c ; same thing; include last byte
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jr .HandleLoop
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.CopyByte
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ld a, [hli]
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ld [de], a
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inc de
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.HandleLoop
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dec c
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jr nz, .CopyByte
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dec b
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jr nz, .CopyByte
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ret
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SwapBytes: ; 0x3034
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; swap bc bytes between hl and de
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.Loop
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; stash [hl] away on the stack
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ld a, [hl]
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push af
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; copy a byte from [de] to [hl]
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ld a, [de]
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ld [hli], a
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; retrieve the previous value of [hl]; put it in [de]
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pop af
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ld [de], a
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inc de
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; handle loop stuff
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dec bc
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ld a, b
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or c
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jr nz, .Loop
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ret
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ByteFill: ; 0x3041
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; fill bc bytes with the value of a, starting at hl
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inc b ; we bail the moment b hits 0, so include the last run
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inc c ; same thing; include last byte
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jr .HandleLoop
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.PutByte
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ld [hli], a
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.HandleLoop
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dec c
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jr nz, .PutByte
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dec b
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jr nz, .PutByte
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ret
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GetFarByte: ; 0x304d
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; retrieve a single byte from a:hl, and return it in a.
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; bankswitch to new bank
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ld [hBuffer], a
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ld a, [hROMBank]
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push af
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ld a, [hBuffer]
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rst Bankswitch
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; get byte from new bank
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ld a, [hl]
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ld [hBuffer], a
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; bankswitch to previous bank
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pop af
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rst Bankswitch
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; return retrieved value in a
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ld a, [hBuffer]
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ret
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GetFarHalfword: ; 0x305d
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; retrieve a halfword from a:hl, and return it in hl.
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; bankswitch to new bank
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ld [hBuffer], a
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ld a, [hROMBank]
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push af
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ld a, [hBuffer]
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rst Bankswitch
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; get halfword from new bank, put it in hl
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ld a, [hli]
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ld h, [hl]
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ld l, a
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; bankswitch to previous bank and return
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pop af
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rst Bankswitch
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ret
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; 0x306b
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FarCopyWRAM: ; 306b
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ld [hBuffer], a
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ld a, [rSVBK]
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push af
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ld a, [hBuffer]
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ld [rSVBK], a
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call CopyBytes
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pop af
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ld [rSVBK], a
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ret
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; 307b
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GetFarWRAMByte: ; 307b
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ld [hBuffer], a
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ld a, [rSVBK]
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push af
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ld a, [hBuffer]
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ld [rSVBK], a
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ld a, [hl]
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ld [hBuffer], a
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pop af
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ld [rSVBK], a
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ld a, [hBuffer]
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ret
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; 308d
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GetFarWRAMWord: ; 308d
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ld [hBuffer], a
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ld a, [rSVBK]
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push af
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ld a, [hBuffer]
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ld [rSVBK], a
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ld a, [hli]
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ld h, [hl]
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ld l, a
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pop af
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ld [rSVBK], a
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ret
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; 309d
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