// --------------------- Opcodes 0x90c0+ ---------------------
// Suba/Cmpa/Adda 1tt1nnnx 11eeeeee (tt=type, x=size, eeeeee=Source EA)
int OpAritha(int op)
{
int use=0;
int type=0,size=0,sea=0,dea=0;
char *asr="";
// Suba/Cmpa/Adda/(invalid):
type=(op>>13)&3; if (type>=3) return 1;
size=(op>>8)&1; size++;
dea=(op>>9)&7; dea|=8; // Dest=An
sea=op&0x003f; // Source
// See if we can do this opcode:
if (EaCanRead(sea,size)==0) return 1;
use=OpBase(op,size);
use&=~0x0e00; // Use same opcode for An
if (op!=use) { OpUse(op,use); return 0; } // Use existing handler
OpStart(op,sea); Cycles=(size==2)?6:8;
if(size==2&&(sea<0x10||sea==0x3c)) Cycles+=2;
if(type==1) Cycles=6;
// EA calculation order defines how situations like suba.w (A0)+, A0 get handled.
// different emus act differently in this situation, I couldn't fugure which is right behaviour.
//if (type == 1)
{
EaCalcReadNoSE(-1,0,sea,size,0x003f);
EaCalcReadNoSE(type!=1?10:-1,11,dea,2,0x0e00);
}
#if 0
else
{
// --------------------- Opcodes 0x4a00+ ---------------------
// Emit a Tst opcode, 01001010 xxeeeeee
int OpTst(int op)
{
int sea=0;
int size=0,use=0;
sea=op&0x003f;
size=(op>>6)&3; if (size>=3) return 1;
// See if we can do this opcode:
if (EaCanWrite(sea)==0||EaAn(sea)) return 1;
use=OpBase(op,size);
if (op!=use) { OpUse(op,use); return 0; } // Use existing handler
OpStart(op,sea); Cycles=4;
EaCalc ( 0,0x003f,sea,size,1);
EaRead ( 0, 0,sea,size,0x003f,1);
ot(" adds r0,r0,#0 ;@ Defines NZ, clears CV\n");
ot(" mrs r10,cpsr ;@ r10=flags\n");
ot("\n");
OpEnd(sea);
return 0;
}
// Asr/Lsr/Roxr/Ror etc EA - 11100ttd 11eeeeee
int OpAsrEa(int op)
{
int use=0,type=0,dir=0,ea=0,size=1;
type=(op>>9)&3;
dir =(op>>8)&1;
ea = op&0x3f;
if (ea<0x10) return 1;
// See if we can do this opcode:
if (EaCanRead(ea,0)==0) return 1;
if (EaCanWrite(ea)==0) return 1;
use=OpBase(op,size);
if (op!=use) { OpUse(op,use); return 0; } // Use existing handler
OpStart(op,ea); Cycles=6; // EmitAsr() will add 2
EaCalc (11,0x003f,ea,size,earwt_shifted_up);
EaRead (11, 0,ea,size,0x003f,earwt_shifted_up);
EmitAsr(op,type,dir,1,size,0);
EaWrite(11, 0,ea,size,0x003f,earwt_shifted_up);
OpEnd(ea);
return 0;
}
// --------------------- Opcodes 0x4880+ ---------------------
// Emit an Ext opcode, 01001000 1x000nnn
int OpExt(int op)
{
int ea=0;
int size=0,use=0;
int shift=0;
ea=op&0x0007;
size=(op>>6)&1;
shift=32-(8<<size);
use=OpBase(op,size);
if (op!=use) { OpUse(op,use); return 0; } // Use existing handler
OpStart(op); Cycles=4;
EaCalc (11,0x0007,ea,size+1,earwt_msb_dont_care);
EaRead (11, 0,ea,size+1,0x0007,earwt_msb_dont_care);
ot(" movs r0,r0,asl #%d\n",shift);
OpGetFlagsNZ(0);
ot(" mov r1,r0,asr #%d\n",shift);
ot("\n");
EaWrite(11, 1,ea,size+1,0x0007,earwt_msb_dont_care);
OpEnd();
return 0;
}
// --------------------- Opcodes 0x4880+ ---------------------
// Emit an Ext opcode, 01001000 1x000nnn
int OpExt(int op)
{
int ea=0;
int size=0,use=0;
int shift=0;
ea=op&0x0007;
size=(op>>6)&1;
shift=32-(8<<size);
use=OpBase(op,size);
if (op!=use) { OpUse(op,use); return 0; } // Use existing handler
OpStart(op); Cycles=4;
EaCalc (11,0x0007,ea,size+1,0,0);
EaRead (11, 0,ea,size+1,0x0007,0,0);
ot(" mov r0,r0,asl #%d\n",shift);
ot(" adds r0,r0,#0 ;@ Defines NZ, clears CV\n");
ot(" mrs r10,cpsr ;@ r10=flags\n");
ot(" mov r1,r0,asr #%d\n",shift);
ot("\n");
EaWrite(11, 1,ea,size+1,0x0007,0,0);
OpEnd();
return 0;
}
// --------------------- Opcodes 0x4a00+ ---------------------
// Emit a Tst opcode, 01001010 xxeeeeee
int OpTst(int op)
{
int sea=0;
int size=0,use=0;
sea=op&0x003f;
size=(op>>6)&3; if (size>=3) return 1;
// See if we can do this opcode:
if (EaCanWrite(sea)==0||EaAn(sea)) return 1;
use=OpBase(op,size);
if (op!=use) { OpUse(op,use); return 0; } // Use existing handler
OpStart(op,sea); Cycles=4;
EaCalc (0,0x003f,sea,size,earwt_shifted_up);
EaRead (0, 0,sea,size,0x003f,earwt_shifted_up,1);
OpGetFlagsNZ(0);
ot("\n");
OpEnd(sea);
return 0;
}
// 01001000 00eeeeee - nbcd <ea>
int OpNbcd(int op)
{
int use=0;
int ea=0;
ea=op&0x3f;
if(EaCanWrite(ea)==0||EaAn(ea)) return 1;
use=OpBase(op,0);
if(op!=use) { OpUse(op,use); return 0; } // Use existing handler
OpStart(op,ea); Cycles=6;
if(ea >= 8) Cycles+=2;
EaCalcReadNoSE(10,0,ea,0,0x003f);
// this is rewrite of Musashi's code
ot(" ldr r2,[r7,#0x4c]\n");
ot(" bic r9,r9,#0xb0000000 ;@ clear all flags, except Z\n");
ot(" mov r0,r0,asl #24\n");
ot(" and r2,r2,#0x20000000\n");
ot(" add r2,r0,r2,lsr #5 ;@ add X\n");
ot(" rsb r11,r2,#0x9a000000 ;@ do arithmetic\n");
ot(" cmp r11,#0x9a000000\n");
ot(" beq finish%.4x\n",op);
ot("\n");
ot(" mvn r3,r11,lsr #31 ;@ Undefined V behavior\n",op);
ot(" and r2,r11,#0x0f000000\n");
ot(" cmp r2,#0x0a000000\n");
ot(" andeq r11,r11,#0xf0000000\n");
ot(" addeq r11,r11,#0x10000000\n");
ot(" and r3,r3,r11,lsr #31 ;@ Undefined V behavior part II\n",op);
ot(" movs r1,r11,asr #24\n");
ot(" bicne r9,r9,#0x40000000 ;@ Z\n");
ot(" orr r9,r9,r3,lsl #28 ;@ save V\n",op);
ot(" orr r9,r9,#0x20000000 ;@ C\n");
ot("\n");
EaWrite(10, 1, ea,0,0x3f,0,0);
ot("finish%.4x%s\n",op,ms?"":":");
ot(" tst r11,r11\n");
ot(" orrmi r9,r9,#0x80000000 ;@ N\n");
ot(" str r9,[r7,#0x4c] ;@ Save X\n");
ot("\n");
OpEnd(ea);
return 0;
}
// --------------------- Opcodes 0x50c0+ ---------------------
// Emit a Set cc opcode, 0101cccc 11eeeeee
int OpSet(int op)
{
int cc=0,ea=0;
int size=0,use=0,changed_cycles=0;
const char *cond;
cc=(op>>8)&15;
ea=op&0x003f;
if ((ea&0x38)==0x08) return 1; // dbra, not scc
// See if we can do this opcode:
if (EaCanWrite(ea)==0) return 1;
use=OpBase(op,size);
if (op!=use) { OpUse(op,use); return 0; } // Use existing handler
changed_cycles=ea<8 && cc>=2;
OpStart(op,ea,0,changed_cycles); Cycles=8;
if (ea<8) Cycles=4;
switch (cc)
{
case 0x00: // T
ot(" mvn r1,#0\n");
if (ea<8) Cycles+=2;
break;
case 0x01: // F
ot(" mov r1,#0\n");
break;
default:
ot(" mov r1,#0\n");
cond=TestCond(cc);
ot(" mvn%s r1,#0\n",cond);
if (ea<8) ot(" sub%s r5,r5,#2 ;@ Extra cycles\n",cond);
break;
}
ot("\n");
eawrite_check_addrerr=1;
EaCalc (0,0x003f, ea,size,earwt_msb_dont_care);
EaWrite(0, 1, ea,size,0x003f,earwt_msb_dont_care);
opend_op_changes_cycles=changed_cycles;
OpEnd(ea,0);
return 0;
}
int OpTas(int op, int gen_special)
{
int ea=0;
int use=0;
ea=op&0x003f;
// See if we can do this opcode:
if (EaCanWrite(ea)==0 || EaAn(ea)) return 1;
use=OpBase(op,0);
if (op!=use) { OpUse(op,use); return 0; } // Use existing handler
if (!gen_special) OpStart(op,ea);
else
ot("Op%.4x_%s\n", op, ms?"":":");
Cycles=4;
if(ea>=8) Cycles+=10;
EaCalc (11,0x003f,ea,0,1);
EaRead (11, 1,ea,0,0x003f,1);
ot(" adds r1,r1,#0 ;@ Defines NZ, clears CV\n");
OpGetFlags(0,0);
ot("\n");
#if CYCLONE_FOR_GENESIS
// the original Sega hardware ignores write-back phase (to memory only)
if (ea < 0x10 || gen_special) {
#endif
ot(" orr r1,r1,#0x80000000 ;@ set bit7\n");
EaWrite(11, 1,ea,0,0x003f,1);
#if CYCLONE_FOR_GENESIS
}
#endif
OpEnd(ea);
#if (CYCLONE_FOR_GENESIS == 2)
if (!gen_special && ea >= 0x10) {
OpTas(op, 1);
}
#endif
return 0;
}
// --------------------- Opcodes 0x0100+ ---------------------
// Emit a Btst (Register) opcode 0000nnn1 ttaaaaaa
int OpBtstReg(int op)
{
int use=0;
int type=0,sea=0,tea=0;
int size=0;
type=(op>>6)&3; // Btst/Bchg/Bclr/Bset
// Get source and target EA
sea=(op>>9)&7;
tea=op&0x003f;
if (tea<0x10) size=2; // For registers, 32-bits
if ((tea&0x38)==0x08) return 1; // movep
// See if we can do this opcode:
if (EaCanRead(tea,0)==0) return 1;
if (type>0)
{
if (EaCanWrite(tea)==0) return 1;
}
use=OpBase(op,size);
use&=~0x0e00; // Use same handler for all registers
if (op!=use) { OpUse(op,use); return 0; } // Use existing handler
OpStart(op,tea);
if(type==1||type==3) {
Cycles=8;
} else {
Cycles=type?8:4;
if(size>=2) Cycles+=2;
}
EaCalcRead(-1,11,sea,0,0x0e00,earwt_msb_dont_care);
EaCalcRead((type>0)?8:-1,0,tea,size,0x003f,earwt_msb_dont_care);
if (tea>=0x10)
ot(" and r11,r11,#7 ;@ mem - do mod 8\n"); // size always 0
else ot(" and r11,r11,#31 ;@ reg - do mod 32\n"); // size always 2
ot("\n");
ot(" mov r1,#1\n");
ot(" tst r0,r1,lsl r11 ;@ Do arithmetic\n");
ot(" bicne r10,r10,#0x40000000\n");
ot(" orreq r10,r10,#0x40000000 ;@ Get Z flag\n");
ot("\n");
if (type>0)
{
if (type==1) ot(" eor r1,r0,r1,lsl r11 ;@ Toggle bit\n");
if (type==2) ot(" bic r1,r0,r1,lsl r11 ;@ Clear bit\n");
if (type==3) ot(" orr r1,r0,r1,lsl r11 ;@ Set bit\n");
ot("\n");
EaWrite(8,1,tea,size,0x003f,earwt_msb_dont_care);
}
OpEnd(tea);
return 0;
}
// --------------------- Opcodes 0x4000+ ---------------------
int OpNeg(int op)
{
// 01000tt0 xxeeeeee (tt=negx/clr/neg/not, xx=size, eeeeee=EA)
int type=0,size=0,ea=0,use=0;
type=(op>>9)&3;
ea =op&0x003f;
size=(op>>6)&3; if (size>=3) return 1;
// See if we can do this opcode:
if (EaCanRead (ea,size)==0||EaAn(ea)) return 1;
if (EaCanWrite(ea )==0) return 1;
use=OpBase(op,size);
if (op!=use) { OpUse(op,use); return 0; } // Use existing handler
OpStart(op,ea); Cycles=size<2?4:6;
if(ea >= 0x10) Cycles*=2;
EaCalc (11,0x003f,ea,size,earwt_msb_dont_care);
if (type!=1) EaRead (11,0,ea,size,0x003f,earwt_msb_dont_care); // Don't need to read for 'clr' (or do we, for a dummy read?)
if (type==1) ot("\n");
if (type==0)
{
ot(";@ Negx:\n");
GetXBit(1);
if(size!=2) ot(" mov r0,r0,asl #%i\n",size?16:24);
ot(" rscs r1,r0,#0 ;@ do arithmetic\n");
ot(" orr r3,r10,#0xb0000000 ;@ for old Z\n");
OpGetFlags(1,1,0);
if(size!=2) {
ot(" movs r1,r1,asr #%i\n",size?16:24);
ot(" orreq r10,r10,#0x40000000 ;@ possily missed Z\n");
}
ot(" andeq r10,r10,r3 ;@ fix Z\n");
ot("\n");
}
if (type==1)
{
ot(";@ Clear:\n");
ot(" mov r1,#0\n");
ot(" mov r10,#0x40000000 ;@ NZCV=0100\n");
ot("\n");
}
if (type==2)
{
ot(";@ Neg:\n");
if(size!=2) ot(" mov r0,r0,asl #%i\n",size?16:24);
ot(" rsbs r1,r0,#0\n");
OpGetFlags(1,1);
if(size!=2) ot(" mov r1,r1,asr #%i\n",size?16:24);
ot("\n");
}
if (type==3)
{
ot(";@ Not:\n");
if(size!=2) {
ot(" mov r0,r0,asl #%i\n",size?16:24);
ot(" mvns r1,r0,asr #%i\n",size?16:24);
}
else
ot(" mvns r1,r0\n");
OpGetFlagsNZ(1);
ot("\n");
}
if (type==1) eawrite_check_addrerr=1;
EaWrite(11, 1,ea,size,0x003f,earwt_msb_dont_care);
OpEnd(ea);
return 0;
}
// --------------------- Opcodes 0x0800+ ---------------------
// Emit a Btst/Bchg/Bclr/Bset (Immediate) opcode 00001000 ttaaaaaa nn
int OpBtstImm(int op)
{
int type=0,sea=0,tea=0;
int use=0;
int size=0;
type=(op>>6)&3;
// Get source and target EA
sea= 0x003c;
tea=op&0x003f;
if (tea<0x10) size=2; // For registers, 32-bits
// See if we can do this opcode:
if (EaCanRead(tea,0)==0||EaAn(tea)||tea==0x3c) return 1;
if (type>0)
{
if (EaCanWrite(tea)==0) return 1;
}
use=OpBase(op,size);
if (op!=use) { OpUse(op,use); return 0; } // Use existing handler
OpStart(op,sea,tea);
ot("\n");
EaCalcRead(-1,0,sea,0,0,earwt_msb_dont_care);
ot(" mov r11,#1\n");
ot(" bic r10,r10,#0x40000000 ;@ Blank Z flag\n");
if (tea>=0x10)
ot(" and r0,r0,#7 ;@ mem - do mod 8\n"); // size always 0
else ot(" and r0,r0,#0x1F ;@ reg - do mod 32\n"); // size always 2
ot(" mov r11,r11,lsl r0 ;@ Make bit mask\n");
ot("\n");
if(type==1||type==3) {
Cycles=12;
} else {
Cycles=type?12:8;
if(size>=2) Cycles+=2;
}
EaCalcRead((type>0)?8:-1,0,tea,size,0x003f,earwt_msb_dont_care);
ot(" tst r0,r11 ;@ Do arithmetic\n");
ot(" orreq r10,r10,#0x40000000 ;@ Get Z flag\n");
ot("\n");
if (type>0)
{
if (type==1) ot(" eor r1,r0,r11 ;@ Toggle bit\n");
if (type==2) ot(" bic r1,r0,r11 ;@ Clear bit\n");
if (type==3) ot(" orr r1,r0,r11 ;@ Set bit\n");
ot("\n");
EaWrite(8, 1,tea,size,0x003f,earwt_msb_dont_care);
#if CYCLONE_FOR_GENESIS && !MEMHANDLERS_CHANGE_CYCLES
// this is a bit hacky (device handlers might modify cycles)
if (tea==0x38||tea==0x39)
ot(" ldr r5,[r7,#0x5c] ;@ Load Cycles\n");
#endif
}
OpEnd(sea,tea);
return 0;
}
// --------------------- Opcodes 0x5000+ ---------------------
int OpAddq(int op)
{
// 0101nnnt xxeeeeee (nnn=#8,1-7 t=addq/subq xx=size, eeeeee=EA)
int num=0,type=0,size=0,ea=0;
int use=0;
char count[16]="";
int shift=0;
num =(op>>9)&7; if (num==0) num=8;
type=(op>>8)&1;
size=(op>>6)&3; if (size>=3) return 1;
ea = op&0x3f;
// See if we can do this opcode:
if (EaCanRead (ea,size)==0) return 1;
if (EaCanWrite(ea) ==0) return 1;
if (size == 0 && EaAn(ea) ) return 1;
use=OpBase(op,size,1);
if (num!=8) use|=0x0e00; // If num is not 8, use same handler
if (op!=use) { OpUse(op,use); return 0; } // Use existing handler
OpStart(op,ea);
Cycles=ea<8?4:8;
if(type==0&&size==1) Cycles=ea<0x10?4:8;
if(size>=2) Cycles=ea<0x10?8:12;
if (size>0 && (ea&0x38)==0x08) size=2; // addq.w #n,An is also 32-bit
EaCalcReadNoSE(10,0,ea,size,0x003f);
shift=32-(8<<size);
if (num!=8)
{
int lsr=9-shift;
ot(" and r2,r8,#0x0e00 ;@ Get quick value\n");
if (lsr>=0) sprintf(count,"r2,lsr #%d", lsr);
else sprintf(count,"r2,lsl #%d", -lsr);
ot("\n");
}
else
{
sprintf(count,"#0x%.4x",8<<shift);
}
if (size<2) ot(" mov r0,r0,asl #%d\n\n",size?16:24);
if (type==0) ot(" adds r1,r0,%s\n",count);
if (type==1) ot(" subs r1,r0,%s\n",count);
if ((ea&0x38)!=0x08) OpGetFlags(type,1);
ot("\n");
EaWrite(10, 1, ea,size,0x003f,1);
OpEnd(ea);
return 0;
}
// --------------------- Opcodes 0x0000+ ---------------------
// Emit an Ori/And/Sub/Add/Eor/Cmp Immediate opcode, 0000ttt0 ssaaaaaa
int OpArith(int op)
{
int type=0,size=0;
int sea=0,tea=0;
int use=0;
char *shiftstr="";
// Get source and target EA
type=(op>>9)&7; if (type==4 || type>=7) return 1;
size=(op>>6)&3; if (size>=3) return 1;
sea= 0x003c;
tea=op&0x003f;
// See if we can do this opcode:
if (EaCanRead(tea,size)==0) return 1;
if (EaCanWrite(tea)==0 || EaAn(tea)) return 1;
use=OpBase(op,size);
if (op!=use) { OpUse(op,use); return 0; } // Use existing handler
OpStart(op, sea, tea); Cycles=4;
// imm must be read first
EaCalcReadNoSE(-1,10,sea,size,0);
EaCalcReadNoSE((type!=6)?11:-1,0,tea,size,0x003f);
if (size<2) shiftstr=(char *)(size?",asl #16":",asl #24");
if (size<2) ot(" mov r10,r10,asl #%i\n",size?16:24);
ot(";@ Do arithmetic:\n");
if (type==0) ot(" orr r1,r10,r0%s\n",shiftstr);
if (type==1) ot(" and r1,r10,r0%s\n",shiftstr);
if (type==2||type==6)
ot(" rsbs r1,r10,r0%s ;@ Defines NZCV\n",shiftstr);
if (type==3) ot(" adds r1,r10,r0%s ;@ Defines NZCV\n",shiftstr);
if (type==5) ot(" eor r1,r10,r0%s\n",shiftstr);
if (type<2 || type==5) ot(" adds r1,r1,#0 ;@ Defines NZ, clears CV\n"); // 0,1,5
if (type< 2) OpGetFlags(0,0); // Ori/And
if (type==2) OpGetFlags(1,1); // Sub: Subtract/X-bit
if (type==3) OpGetFlags(0,1); // Add: X-bit
if (type==5) OpGetFlags(0,0); // Eor
if (type==6) OpGetFlags(1,0); // Cmp: Subtract
ot("\n");
if (type!=6)
{
EaWrite(11, 1, tea,size,0x003f,1);
}
// Correct cycles:
if (type==6)
{
if (size>=2 && tea<0x10) Cycles+=2;
}
else
{
if (size>=2) Cycles+=4;
if (tea>=8) Cycles+=4;
if (type==1 && size>=2 && tea<8) Cycles-=2;
}
OpEnd(sea,tea);
return 0;
}
// --------------------- Opcodes 0x80c0+ ---------------------
int OpMul(int op)
{
// Div/Mul: 1m00nnns 11eeeeee (m=Mul, nnn=Register Dn, s=signed, eeeeee=EA)
int type=0,rea=0,sign=0,ea=0;
int use=0;
type=(op>>14)&1; // div/mul
rea =(op>> 9)&7;
sign=(op>> 8)&1;
ea = op&0x3f;
// See if we can do this opcode:
if (EaCanRead(ea,1)==0||EaAn(ea)) return 1;
use=OpBase(op,1);
use&=~0x0e00; // Use same for all registers
if (op!=use) { OpUse(op,use); return 0; } // Use existing handler
OpStart(op,ea);
if(type) Cycles=54;
else Cycles=sign?158:140;
EaCalcReadNoSE(-1,0,ea,1,0x003f);
EaCalc(10,0x0e00,rea, 2);
EaRead(10, 2,rea, 2,0x0e00);
ot(" movs r1,r0,asl #16\n");
if (type==0) // div
{
// the manual says C is always cleared, but neither Musashi nor FAME do that
//ot(" bic r9,r9,#0x20000000 ;@ always clear C\n");
ot(" beq divzero%.4x ;@ division by zero\n",op);
ot("\n");
if (sign)
{
ot(" mov r11,#0 ;@ r11 = 1 or 2 if the result is negative\n");
ot(" tst r2,r2\n");
ot(" orrmi r11,r11,#2\n");
ot(" rsbmi r2,r2,#0 ;@ Make r2 positive\n");
ot("\n");
ot(" movs r0,r1,asr #16\n");
ot(" orrmi r11,r11,#1\n");
ot(" rsbmi r0,r0,#0 ;@ Make r0 positive\n");
ot("\n");
ot(";@ detect the nasty 0x80000000 / -1 situation\n");
ot(" mov r3,r2,asr #31\n");
ot(" eors r3,r3,r1,asr #16\n");
ot(" beq wrendofop%.4x\n",op);
}
else
{
ot(" mov r0,r1,lsr #16 ;@ use only 16 bits of divisor\n");
}
ot("\n");
ot(";@ Divide r2 by r0\n");
ot(" mov r3,#0\n");
ot(" mov r1,r0\n");
ot("\n");
ot(";@ Shift up divisor till it's just less than numerator\n");
ot("Shift%.4x%s\n",op,ms?"":":");
ot(" cmp r1,r2,lsr #1\n");
ot(" movls r1,r1,lsl #1\n");
ot(" bcc Shift%.4x\n",op);
ot("\n");
ot("Divide%.4x%s\n",op,ms?"":":");
ot(" cmp r2,r1\n");
ot(" adc r3,r3,r3 ;@ Double r3 and add 1 if carry set\n");
ot(" subcs r2,r2,r1\n");
ot(" teq r1,r0\n");
ot(" movne r1,r1,lsr #1\n");
ot(" bne Divide%.4x\n",op);
ot("\n");
ot(";@r3==quotient,r2==remainder\n");
if (sign)
{
// sign correction
ot(" and r1,r11,#1\n");
ot(" teq r1,r11,lsr #1\n");
ot(" rsbne r3,r3,#0 ;@ negate if quotient is negative\n");
ot(" tst r11,#2\n");
ot(" rsbne r2,r2,#0 ;@ negate the remainder if divident was negative\n");
ot("\n");
// signed overflow check
ot(" mov r1,r3,asl #16\n");
ot(" cmp r3,r1,asr #16 ;@ signed overflow?\n");
ot(" orrne r9,r9,#0x10000000 ;@ set overflow flag\n");
ot(" bne endofop%.4x ;@ overflow!\n",op);
ot("\n");
ot("wrendofop%.4x%s\n",op,ms?"":":");
}
else
{
// overflow check
ot(" movs r1,r3,lsr #16 ;@ check for overflow condition\n");
ot(" orrne r9,r9,#0x10000000 ;@ set overflow flag\n");
ot(" bne endofop%.4x ;@ overflow!\n",op);
ot("\n");
}
ot(" mov r1,r3,lsl #16 ;@ Clip to 16-bits\n");
ot(" adds r1,r1,#0 ;@ Defines NZ, clears CV\n");
OpGetFlags(0,0);
ot(" mov r1,r1,lsr #16\n");
ot(" orr r1,r1,r2,lsl #16 ;@ Insert remainder\n");
}
if (type==1)
{
ot(";@ Get 16-bit signs right:\n");
ot(" mov r0,r1,%s #16\n",sign?"asr":"lsr");
ot(" mov r2,r2,lsl #16\n");
ot(" mov r2,r2,%s #16\n",sign?"asr":"lsr");
ot("\n");
ot(" mul r1,r2,r0\n");
ot(" adds r1,r1,#0 ;@ Defines NZ, clears CV\n");
OpGetFlags(0,0);
}
ot("\n");
EaWrite(10, 1,rea, 2,0x0e00,1);
if (type==0) ot("endofop%.4x%s\n",op,ms?"":":");
OpEnd(ea);
if (type==0) // div
{
ot("divzero%.4x%s\n",op,ms?"":":");
ot(" mov r0,#5 ;@ Divide by zero\n");
ot(" bl Exception\n");
Cycles+=38;
OpEnd(ea);
ot("\n");
}
return 0;
}
// --------------------- Opcodes 0x8000+ ---------------------
// 1t0tnnnd xxeeeeee (tt=type:or/sub/and/add xx=size, eeeeee=EA)
int OpArithReg(int op)
{
int use=0;
int type=0,size=0,dir=0,rea=0,ea=0;
char *asl="";
char *strop=0;
type=(op>>12)&5;
rea =(op>> 9)&7;
dir =(op>> 8)&1; // er,re
size=(op>> 6)&3; if (size>=3) return 1;
ea = op&0x3f;
if (dir && ea<0x10) return 1; // addx/subx opcode
// See if we can do this opcode:
if (dir==0 && EaCanRead (ea,size)==0) return 1;
if (dir && EaCanWrite(ea)==0) return 1;
if ((size==0||!(type&1))&&EaAn(ea)) return 1;
use=OpBase(op,size);
use&=~0x0e00; // Use same opcode for Dn
if (op!=use) { OpUse(op,use); return 0; } // Use existing handler
OpStart(op,ea); Cycles=4;
EaCalcReadNoSE(dir?10:-1,0,ea,size,0x003f);
EaCalcReadNoSE(dir?-1:10,1,rea,size,0x0e00);
ot(";@ Do arithmetic:\n");
if (type==0) strop = "orr";
if (type==1) strop = (char *) (dir ? "subs" : "rsbs");
if (type==4) strop = "and";
if (type==5) strop = "adds";
if (size==0) asl=",asl #24";
if (size==1) asl=",asl #16";
if (size<2) ot(" mov r0,r0%s\n",asl);
ot(" %s r1,r0,r1%s\n",strop,asl);
if ((type&1)==0) ot(" adds r1,r1,#0 ;@ Defines NZ, clears CV\n");
OpGetFlags(type==1,type&1); // 1==subtract
ot("\n");
ot(";@ Save result:\n");
if (size<2) ot(" mov r1,r1,asr #%d\n",size?16:24);
if (dir) EaWrite(10, 1, ea,size,0x003f,0,0);
else EaWrite(10, 1,rea,size,0x0e00,0,0);
if(rea==ea) {
if(ea<8) Cycles=(size>=2)?8:4; else Cycles+=(size>=2)?26:14;
} else if(dir) {
Cycles+=4;
if(size>=2) Cycles+=4;
} else {
if(size>=2) {
Cycles+=2;
if(ea<0x10||ea==0x3c) Cycles+=2;
}
}
OpEnd(ea);
return 0;
}
// --------------------- Opcodes 0x50c0+ ---------------------
// Emit a Set cc opcode, 0101cccc 11eeeeee
int OpSet(int op)
{
int cc=0,ea=0;
int size=0,use=0,changed_cycles=0;
static const char * const cond[16]=
{
"al","", "hi","ls","cc","cs","ne","eq",
"vc","vs","pl","mi","ge","lt","gt","le"
};
cc=(op>>8)&15;
ea=op&0x003f;
if ((ea&0x38)==0x08) return 1; // dbra, not scc
// See if we can do this opcode:
if (EaCanWrite(ea)==0) return 1;
use=OpBase(op,size);
if (op!=use) { OpUse(op,use); return 0; } // Use existing handler
changed_cycles=ea<8 && cc>=2;
OpStart(op,ea,0,changed_cycles); Cycles=8;
if (ea<8) Cycles=4;
if (cc)
ot(" mov r1,#0\n");
switch (cc)
{
case 0: // T
ot(" mvn r1,#0\n");
if (ea<8) Cycles+=2;
break;
case 1: // F
break;
case 2: // hi
ot(" tst r10,#0x60000000 ;@ hi: !C && !Z\n");
ot(" mvneq r1,r1\n");
if (ea<8) ot(" subeq r5,r5,#2 ;@ Extra cycles\n");
break;
case 3: // ls
ot(" tst r10,#0x60000000 ;@ ls: C || Z\n");
ot(" mvnne r1,r1\n");
if (ea<8) ot(" subne r5,r5,#2 ;@ Extra cycles\n");
break;
default:
ot(";@ Is the condition true?\n");
ot(" msr cpsr_flg,r10 ;@ ARM flags = 68000 flags\n");
ot(" mvn%s r1,r1\n",cond[cc]);
if (ea<8) ot(" sub%s r5,r5,#2 ;@ Extra cycles\n",cond[cc]);
break;
}
ot("\n");
eawrite_check_addrerr=1;
EaCalc (0,0x003f, ea,size,0,0);
EaWrite(0, 1, ea,size,0x003f,0,0);
opend_op_changes_cycles=changed_cycles;
OpEnd(ea,0);
return 0;
}