CPU addressing modes

Comments:

ADDR_ZP, ADDR_ZPX, ADDR_ZPY, ADDR_ABS, ADDR_ABSX, and ADDR_ABSY all look okay. You might want to & 0xFF the PC address result on ADDR_ZP, depending upon how high g_cpu.pc can go.

Your ADDR_INDX and ADDR_INDY are hard to interpret unless you give more detail about how they're being used. They should be following this logic (best to explain it, rather than just give you formulae). Assume the following memory layout:

memory[$00] = $FA
memory[$01] = $80
memory[$02] = $81
memory[$03] = $C0
memory[$80FA] = $EE
memory[$80FB] = $FF
memory[$8180] = $CC
memory[$8181] = $BB
memory[$C081] = $AA

For ADDR_INDX:

LDX #0
LDA ($00,X)

Effective address of $80FA. A = data read from $80FA, thus A = $EE.

LDX #1
LDA ($00,X)

Effective address of $8180. A = data read from $8180, thus A = $CC.

LDX #1
LDA ($01,X)

Effective address of $C081. A = data read from $C081, thus A = $AA.



For ADDR_INDY:

LDY #0
LDA ($00),Y

Effective address of $80FA + $00. A = data read from $80FA, thus A = $EE.

LDY #1
LDA ($00),Y

Effective address of $80FA + $01. A = data read from $80FB, thus A = $FF.

LDY #1
LDA ($01),Y

Effective address of $8180 + $01. A = data read from $8181, thus A = $BB.

An easier way to remember the two addressing modes: (ZP,X) is called pre-indexed, and (ZP),Y is called post-indexed.


Don't forget about cycle additions in the case of page wrapping, too. Details:

http://www.obelisk.demon.co.uk/6502/reference.html#LDA