gbdk-2020 | GameBoy Development Kit |
| download: https://git.y1.nz/archives/gbdk.tar.gz | |
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gbdk-lib/libc/targets/mos6502/nes/mapper_macros.s
1 ;
2 ; Define for mapper register
3 ;
4 .define MAPPER_WRITE_REG ".identity"
5
6 ;
7 ; Set PRG bank to A register
8 ;
9 ; Trashes Y register.
10 ;
11 .macro SWITCH_PRG0_A
12 tay
13 sta .identity,Y
14 .endm
15
16 ;
17 ; Set PRG bank to Y register
18 ;
19 ; Trashes A register.
20 ;
21 .macro SWITCH_PRG0_Y
22 tya
23 sta .identity,Y
24 .endm
25
26 ;
27 ; Modify PPU high address bits in A based on VRAM switch config
28 ;
29 ;
30 ;
31 .macro SET_PPUHI_ADDRESS_A ?.skip
32 .ifdef NES_WINDOW_LAYER
33 bit *__current_vram_cfg_write
34 bpl .skip
35 ora #PPUHI_WIN
36 .skip:
37 .endif
38 .endm
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