Do you support custom opcodes?

Question

Do you support custom opcodes?

GZYangKui opened this issue 8 months ago · comments

I am implementing an emulator and would like to customize some exclusive operation codes for the emulator. Do you currently support custom operation codes?

GrantMTG · Answer 1 · Mon Nov 06 2023 00:15:18 GMT+0800 (China Standard Time)

Define Constant Byte doesn't work for you?

杨奎 · Answer 2 · Mon Nov 06 2023 10:56:21 GMT+0800 (China Standard Time)

I have defined a constant with a value equal to $55 in my emulator, which is a debugging instruction. Then, when I embed this constant into the program and compile using dasm, the following error will occur:

BMAN. s (8): error: Unknown Mnemonic 'DEBUG'
BMAN. s (18): error: Unknown Mnemonic 'DEBUG'

DEBUG EQU $ff
RESET:
SEI; Reset PPU Disable NMI, turn off background and sprites
LDA # 0
STA PPU_ CTRL_ REG2
STA PPU_ CTRL_ REG1
CLD; The NES 6502 CPU has no BCD mode, reset the flag just in case
LDX # $FF; Set the stack pointer to the initial position
TXS
DEBUG

Csaba Fekete · Answer 3 · Mon Nov 06 2023 13:31:37 GMT+0800 (China Standard Time)

Define a macro: MAC DEBUG DC. B $FF ENDM DEBUG Regards 杨奎 ***@***.***> ezt írta (időpont: 2023. nov. 6., H 3:56):

…

I have defined a constant with a value equal to $55 in my emulator, which is a debugging instruction. Then, when I embed this constant into the program and compile using dasm, the following error will occur: BMAN. s (8): error: Unknown Mnemonic 'DEBUG' BMAN. s (18): error: Unknown Mnemonic 'DEBUG' DEBUG EQU $ff RESET: SEI; Reset PPU Disable NMI, turn off background and sprites LDA # 0 STA PPU_ CTRL_ REG2 STA PPU_ CTRL_ REG1 CLD; The NES 6502 CPU has no BCD mode, reset the flag just in case LDX # $FF; Set the stack pointer to the initial position TXS DEBUG — Reply to this email directly, view it on GitHub <#145 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABHO446Q5SW6V3MBRD7PKITYDBGWFAVCNFSM6AAAAAA66IEKN2VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMYTOOJUGAYDQNJVHE> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

GrantMTG · Answer 4 · Mon Nov 06 2023 21:58:23 GMT+0800 (China Standard Time)

A macro is nice and clean, but you shouldn't need it for one line. Just use the equate and make sure the DC.B is not in coilumn 1.

DEBUG EQU is not the same and DC.B.

Assuming DEBUG isn't a reserved word

DEBUG EQU $FF

DC.B DEBUG

would also work. Whichever you prefer.