// -----------------------------------------------------------------------
// This function loops until cycles <= 0.
// Ignores bad opcodes, doesn't return anything.
asm void N6502_Exec()
{
mflr r14 // save our calling address
entry static __execloop
subc. r28,r28,r4 // decrease cycles by r4
ble exec_end
fetchbyte(r5) // get next instruction from PC
slwi r5,r5,2 // use opcode as index into jumptable (r16)
lwzx r7,r5,r16
mtlr r7
blr // jump to opcode handler
entry static __execbad
#ifdef TrapBadOps
subic r24,r24,1 // set pc to offending instruction
b exec_end
#else
li r4,4
b __execloop // ignore, charge nop (?) cycles.
#endif
exec_end:
mtlr r14 // restore caller address (the LR)
blr
}
uint8 memz80_fetch_mem_byte(uint16 addr)
{
return (fetchbyte(cpuz80_bank | (addr - 0x8000)));
}
