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Add mapper 422submapper 4.

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NewRisingSun
2025-11-28 12:25:24 +01:00
parent aabeaf1d03
commit d0c3023e14
1 changed files with 5 additions and 0 deletions
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5
src/boards/126_422_534.c
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@@ -29,6 +29,8 @@
Submapper 0: Normal connection
Submapper 1: PRG A21 (2 MiB bank) selects between two 1 MiB chips
Submapper 2: Register bit 6001.2 (undocumented in data sheet) selects between two 1 MiB chips
Submapper 3: 6000.2 substitutes PRG A14 and CHR A14 with 6000.5
Submapper 4: LD822 PCB - CHR A20..A18 = PRG A20..A18
Both ASICs invert the register bit that selects PRG A21 (6000.5), hence "EXPREGS[0] ^0x20".
*/
@@ -81,6 +83,9 @@ static void wrapCHR(uint32 A, uint8 V) {
int chrOR; /* outer CHR bank */
if (reverseCHR_A18_A19) /* Mapper 126 swaps CHR A18 and A19 */
chrOR =(EXPREGS[0] <<4 &0x080 | (EXPREGS[0] ^0x20) <<3 &0x100 | EXPREGS[0] <<5 &0x200) &~chrAND;
else
if (submapper == 4) /* LD822 PCB - CHR A20..A18 = PRG A20..A18 */
chrOR =(EXPREGS[0] <<4 &0x080 | EXPREGS[0] <<7 &0x100 | ~EXPREGS[0] <<4 &0x200 | EXPREGS[0] <<6 &0x400) &~chrAND;
else
chrOR =((EXPREGS[0] ^0x20) <<4 &0x380 | EXPREGS[0] <<8 &0x400) &~chrAND;