// license:BSD-3-Clause // copyright-holders:Miodrag Milanovic /***************************************************************************** * * scmpdasm.c * * National Semiconductor SC/MP CPU Disassembly * *****************************************************************************/ #include "emu.h" #define OP(A) oprom[(A) - PC] #define ARG(A) opram[(A) - PC] CPU_DISASSEMBLE( scmp ) { unsigned PC = pc; UINT8 op = OP(pc++); UINT8 ptr = op & 3; if (BIT(op,7)) { // two bytes instructions char as[10]; char aspr[10]; UINT8 arg = ARG(pc); pc++; if (arg==0x80) { sprintf(as,"E"); } else { if (arg & 0x80) { sprintf(as,"-$%02x",0x100-arg); } else { sprintf(as,"+$%02x",arg); } } sprintf(aspr,"%s(%d)",as,ptr); switch (op) { // Memory Reference Instructions case 0xc0 : sprintf (buffer,"ld %s",as); break; case 0xc1 : case 0xc2 : case 0xc3 : sprintf (buffer,"ld %s",aspr);break; case 0xc5 : case 0xc6 : case 0xc7 : sprintf (buffer,"ld @%s",aspr); break; case 0xc8 : sprintf (buffer,"st %s",as); break; case 0xc9 : case 0xca : case 0xcb : sprintf (buffer,"st %s",aspr);break; case 0xcd : case 0xce : case 0xcf : sprintf (buffer,"st @%s",aspr); break; case 0xd0 : sprintf (buffer,"and %s",as); break; case 0xd1 : case 0xd2 : case 0xd3 : sprintf (buffer,"and %s",aspr);break; case 0xd5 : case 0xd6 : case 0xd7 : sprintf (buffer,"and @%s",aspr); break; case 0xd8 : sprintf (buffer,"or %s",as); break; case 0xd9 : case 0xda : case 0xdb : sprintf (buffer,"or %s",aspr);break; case 0xdd : case 0xde : case 0xdf : sprintf (buffer,"or @%s",aspr); break; case 0xe0 : sprintf (buffer,"xor %s",as); break; case 0xe1 : case 0xe2 : case 0xe3 : sprintf (buffer,"xor %s",aspr);break; case 0xe5 : case 0xe6 : case 0xe7 : sprintf (buffer,"xor @%s",aspr); break; case 0xe8 : sprintf (buffer,"dad %s",as); break; case 0xe9 : case 0xea : case 0xeb : sprintf (buffer,"dad %s",aspr);break; case 0xed : case 0xee : case 0xef : sprintf (buffer,"dad @%s",aspr); break; case 0xf0 : sprintf (buffer,"add %s",as); break; case 0xf1 : case 0xf2 : case 0xf3 : sprintf (buffer,"add %s",aspr);break; case 0xf5 : case 0xf6 : case 0xf7 : sprintf (buffer,"add @%s",aspr); break; case 0xf8 : sprintf (buffer,"cad %s",as); break; case 0xf9 : case 0xfa : case 0xfb : sprintf (buffer,"cad %s",aspr);break; case 0xfd : case 0xfe : case 0xff : sprintf (buffer,"cad @%s",aspr); break; // Memory Increment/Decrement Instructions case 0xa8 : case 0xa9 : case 0xaa : case 0xab : sprintf (buffer,"ild %s",aspr); break; case 0xb8 : case 0xb9 : case 0xba : case 0xbb : sprintf (buffer,"dld %s",aspr); break; // Immediate Instructions case 0xc4 : sprintf (buffer,"ldi $%02x",arg); break; case 0xd4 : sprintf (buffer,"ani $%02x",arg); break; case 0xdc : sprintf (buffer,"ori $%02x",arg); break; case 0xe4 : sprintf (buffer,"xri $%02x",arg); break; case 0xec : sprintf (buffer,"dai $%02x",arg); break; case 0xf4 : sprintf (buffer,"adi $%02x",arg); break; case 0xfc : sprintf (buffer,"cai $%02x",arg); break; // Transfer Instructions case 0x90 : sprintf (buffer,"jmp %s",as);break; case 0x91 : case 0x92 : case 0x93 : sprintf (buffer,"jmp %s",aspr);break; case 0x94 : sprintf (buffer,"jp %s",as); break; case 0x95 : case 0x96 : case 0x97 : sprintf (buffer,"jp %s",aspr); break; case 0x98 : sprintf (buffer,"jz %s",as); break; case 0x99 : case 0x9a : case 0x9b : sprintf (buffer,"jz %s",aspr); break; case 0x9c : sprintf (buffer,"jnz %s",as); break; case 0x9d : case 0x9e : case 0x9f : sprintf (buffer,"jnz %s",aspr); break; // Double-Byte Miscellaneous Instructions case 0x8f: sprintf (buffer,"dly $%02x",arg); break; // Others are illegal default : sprintf (buffer,"illegal"); pc--; break; // Illegal we consider without param } } else { // one byte instructions switch (op) { // Extension Register Instructions case 0x40: sprintf (buffer,"lde"); break; case 0x01: sprintf (buffer,"xae"); break; case 0x50: sprintf (buffer,"ane"); break; case 0x58: sprintf (buffer,"ore"); break; case 0x60: sprintf (buffer,"xre"); break; case 0x68: sprintf (buffer,"dae"); break; case 0x70: sprintf (buffer,"ade"); break; case 0x78: sprintf (buffer,"cae"); break; // Pointer Register Move Instructions case 0x30: case 0x31 :case 0x32: case 0x33: sprintf (buffer,"xpal %d",ptr); break; case 0x34: case 0x35 :case 0x36: case 0x37: sprintf (buffer,"xpah %d",ptr); break; case 0x3c: case 0x3d :case 0x3e: case 0x3f: sprintf (buffer,"xppc %d",ptr); break; // Shift, Rotate, Serial I/O Instructions case 0x19: sprintf (buffer,"sio"); break; case 0x1c: sprintf (buffer,"sr"); break; case 0x1d: sprintf (buffer,"srl"); break; case 0x1e: sprintf (buffer,"rr"); break; case 0x1f: sprintf (buffer,"rrl"); break; // Single Byte Miscellaneous Instructions case 0x00: sprintf (buffer,"halt"); break; case 0x02: sprintf (buffer,"ccl"); break; case 0x03: sprintf (buffer,"scl"); break; case 0x04: sprintf (buffer,"dint"); break; case 0x05: sprintf (buffer,"ien"); break; case 0x06: sprintf (buffer,"csa"); break; case 0x07: sprintf (buffer,"cas"); break; case 0x08: sprintf (buffer,"nop"); break; // Others are illegal default : sprintf (buffer,"illegal"); break; } } return (pc - PC); }