i think i'm having a problem in my jsr and/or rts functions, but i'm not sure, so if someone would look at them, i'd appreciate it:

inline DWORD CPU6502::JSRa () {
    WORD pLoc     = GetParamAbsolute();
    m_registerPC += 2;

    StackPush(HIGH(m_registerPC));
    StackPush(LOW(m_registerPC));
    m_registerPC = pLoc;
    return 6;
}

inline DWORD CPU6502::RTS () {
    BYTE pcLow   = StackPop();
    BYTE pcHigh  = StackPop();
    m_registerPC = MAKE_WORD(pcHigh, pcLow) + 1;
    return 6;
}

GetParamAbsolute() is returning the address contained right after the instruction. maybe thats wrong, i dunno. anyway, thanks.

As far as I can tell they look all right... GetParamAbsolute() should be returning an absolute address (i.e. PRGRAM [PC + 1] | (PRGRAM [PC + 2] << 8), considering PC points to the jsr instruction).

hydesprojects.cjb.net

right, ok...that's what its doing...so the problem is somewhere else in this tangled mess of code :)

Just write a short machine code sequence that has a JSR to an RTS. Step through and verify that the addresses are correct. Should pinpoint the cause(s) of the problem.

On JSRa(), m_registerPC should only be incremented by 1 (a byte before the next opcode). Just look at

m_registerPC = MAKE_WORD(pcHigh, pcLow) + 1;

On RTS() PC is incremented by one cause the pushed PC is just the byte before the actual instruction. So I think you should only increment m_registerPC by one, not two.

Hope this helps. Cya!