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picodrive/cpu/Cyclone/OpArith.cpp
notaz b637c56aad some optimizations 
git-svn-id: file:///home/notaz/opt/svn/PicoDrive@178 be3aeb3a-fb24-0410-a615-afba39da0efa
2007-06-30 22:24:39 +00:00

762 lines
20 KiB
C++
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#include "app.h"
// --------------------- 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);
if (op!=use) { OpUse(op,use); return 0; } // Use existing handler
OpStart(op, sea, tea); Cycles=4;
EaCalc(10,0x0000, sea,size,1);
EaCalc(11,0x003f, tea,size,1);
EaRead(10, 10, sea,size,0,0,0);
EaRead(11, 0, tea,size,0x003f,1);
if (size==0) shiftstr=",asl #24";
else if (size==1) shiftstr=",asl #16";
ot(";@ Do arithmetic:\n");
if (type==0) ot(" orr r1,r0,r10%s\n",shiftstr);
if (type==1) ot(" and r1,r0,r10%s\n",shiftstr);
if (type==2) ot(" subs r1,r0,r10%s ;@ Defines NZCV\n",shiftstr);
if (type==3) ot(" adds r1,r0,r10%s ;@ Defines NZCV\n",shiftstr);
if (type==5) ot(" eor r1,r0,r10%s\n",shiftstr);
if (type==6) ot(" cmp r0,r10%s ;@ Defines NZCV\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 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,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
EaCalc(10,0x003f, ea,size,1);
EaRead(10, 0, ea,size,0x003f,1);
shift=32-(8<<size);
if (num!=8)
{
int lsr=9-shift;
if (lsr>=0) ot(" mov r2,r8,lsr #%d ;@ Get quick value\n", lsr);
else ot(" mov r2,r8,lsl #%d ;@ Get quick value\n",-lsr);
ot(" and r2,r2,#0x%.4x\n",7<<shift);
ot("\n");
strcpy(count,"r2");
}
if (num==8) sprintf(count,"#0x%.4x",8<<shift);
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 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;
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);
use&=~0x0e00; // Use same opcode for Dn
if (op!=use) { OpUse(op,use); return 0; } // Use existing handler
OpStart(op,ea); Cycles=4;
ot(";@ Get r10=EA r11=EA value\n");
EaCalc(10,0x003f, ea,size,1);
EaRead(10, 11, ea,size,0x003f,1);
ot(";@ Get r0=Register r1=Register value\n");
EaCalc( 0,0x0e00,rea,size,1);
EaRead( 0, 1,rea,size,0x0e00,1);
ot(";@ Do arithmetic:\n");
if (type==0) ot(" orr ");
if (type==1) ot(" subs ");
if (type==4) ot(" and ");
if (type==5) ot(" adds ");
if (dir) ot("r1,r11,r1\n");
else ot("r1,r1,r11\n");
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 (dir) EaWrite(10, 1, ea,size,0x003f,1);
else EaWrite( 0, 1,rea,size,0x0e00,1);
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 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);
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;
EaCalc(10,0x003f, ea, 1);
EaRead(10, 10, ea, 1,0x003f);
EaCalc (0,0x0e00,rea, 2,1);
EaRead (0, 2,rea, 2,0x0e00,1);
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(" tst r10,r10\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(" orrmi r11,r11,#1\n");
ot(" rsbmi r10,r10,#0 ;@ Make r10 positive\n");
ot("\n");
ot(" tst r2,r2\n");
ot(" orrmi r11,r11,#2\n");
ot(" rsbmi r2,r2,#0 ;@ Make r2 positive\n");
ot("\n");
}
else
{
ot(" mov r10,r10,lsl #16 ;@ use only 16 bits of divisor\n");
ot(" mov r10,r10,lsr #16\n");
}
ot(";@ Divide r2 by r10\n");
ot(" mov r3,#0\n");
ot(" mov r1,r10\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,r10\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);
}
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(" 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)
{
char *shift="asr";
ot(";@ Get 16-bit signs right:\n");
if (sign==0) { ot(" mov r10,r10,lsl #16\n"); shift="lsr"; }
ot(" mov r2,r2,lsl #16\n");
if (sign==0) ot(" mov r10,r10,lsr #16\n");
ot(" mov r2,r2,%s #16\n",shift);
ot("\n");
ot(" mul r1,r2,r10\n");
ot(" adds r1,r1,#0 ;@ Defines NZ, clears CV\n");
OpGetFlags(0,0);
}
ot("\n");
EaWrite(0, 1,rea, 2,0x0e00,1);
ot("endofop%.4x%s\n",op,ms?"":":");
OpEnd(ea);
ot("divzero%.4x%s\n",op,ms?"":":");
ot(" mov r0,#0x14 ;@ Divide by zero\n");
ot(" bl Exception\n");
Cycles+=38;
OpEnd(ea);
ot("\n");
return 0;
}
// Get X Bit into carry - trashes r2
int GetXBit(int subtract)
{
ot(";@ Get X bit:\n");
ot(" ldrb r2,[r7,#0x45]\n");
if (subtract) ot(" mvn r2,r2,lsl #28 ;@ Invert it\n");
else ot(" mov r2,r2,lsl #28\n");
ot(" msr cpsr_flg,r2 ;@ Get into Carry\n");
ot("\n");
return 0;
}
// --------------------- Opcodes 0x8100+ ---------------------
// 1t00ddd1 0000asss - sbcd/abcd Ds,Dd or -(As),-(Ad)
int OpAbcd(int op)
{
int use=0;
int type=0,sea=0,addr=0,dea=0;
type=(op>>14)&1; // sbcd/abcd
dea =(op>> 9)&7;
addr=(op>> 3)&1;
sea = op &7;
if (addr) { sea|=0x20; dea|=0x20; }
use=op&~0x0e07; // Use same opcode for all registers..
if (sea==0x27||dea==0x27) use=op; // ..except -(a7)
if (op!=use) { OpUse(op,use); return 0; } // Use existing handler
OpStart(op,sea,dea); Cycles=6;
EaCalc( 0,0x0007, sea,0,1);
EaRead( 0, 10, sea,0,0x0007,1);
EaCalc(11,0x0e00, dea,0,1);
EaRead(11, 1, dea,0,0x0e00,1);
ot(" bic r9,r9,#0xb1000000 ;@ clear all flags except old Z\n");
if (type)
{
ot(" ldrb r0,[r7,#0x45] ;@ Get X bit\n");
ot(" mov r3,#0x00f00000\n");
ot(" and r2,r3,r1,lsr #4\n");
ot(" tst r0,#2\n");
ot(" and r0,r3,r10,lsr #4\n");
ot(" add r0,r0,r2\n");
ot(" addne r0,r0,#0x00100000\n");
// ot(" tst r0,#0x00800000\n");
// ot(" orreq r9,r9,#0x01000000 ;@ Undefined V behavior\n");
ot(" cmp r0,#0x00900000\n");
ot(" addhi r0,r0,#0x00600000 ;@ Decimal adjust units\n");
ot(" mov r2,r1,lsr #28\n");
ot(" add r0,r0,r2,lsl #24\n");
ot(" mov r2,r10,lsr #28\n");
ot(" add r0,r0,r2,lsl #24\n");
ot(" cmp r0,#0x09900000\n");
ot(" orrhi r9,r9,#0x20000000 ;@ C\n");
ot(" subhi r0,r0,#0x0a000000\n");
// ot(" and r3,r9,r0,lsr #3 ;@ Undefined V behavior part II\n");
// ot(" orr r9,r9,r3,lsl #4 ;@ V\n");
ot(" movs r0,r0,lsl #4\n");
ot(" orrmi r9,r9,#0x90000000 ;@ Undefined N+V behavior\n"); // this is what Musashi really does
ot(" bicne r9,r9,#0x40000000 ;@ Z flag\n");
}
else
{
ot(" ldrb r0,[r7,#0x45] ;@ Get X bit\n");
ot(" mov r3,#0x00f00000\n");
ot(" and r2,r3,r10,lsr #4\n");
ot(" tst r0,#2\n");
ot(" and r0,r3,r1,lsr #4\n");
ot(" sub r0,r0,r2\n");
ot(" subne r0,r0,#0x00100000\n");
// ot(" tst r0,#0x00800000\n");
// ot(" orreq r9,r9,#0x01000000 ;@ Undefined V behavior\n");
ot(" cmp r0,#0x00900000\n");
ot(" subhi r0,r0,#0x00600000 ;@ Decimal adjust units\n");
ot(" mov r2,r1,lsr #28\n");
ot(" add r0,r0,r2,lsl #24\n");
ot(" mov r2,r10,lsr #28\n");
ot(" sub r0,r0,r2,lsl #24\n");
ot(" cmp r0,#0x09900000\n");
ot(" orrhi r9,r9,#0xa0000000 ;@ N and C\n");
ot(" addhi r0,r0,#0x0a000000\n");
// ot(" and r3,r9,r0,lsr #3 ;@ Undefined V behavior part II\n");
// ot(" orr r9,r9,r3,lsl #4 ;@ V\n");
ot(" movs r0,r0,lsl #4\n");
// ot(" orrmi r9,r9,#0x80000000 ;@ Undefined N behavior\n");
ot(" bicne r9,r9,#0x40000000 ;@ Z flag\n");
}
ot(" mov r2,r9,lsr #28\n");
ot(" strb r2,[r7,#0x45] ;@ Save X bit\n");
EaWrite(11, 0, dea,0,0x0e00,1);
OpEnd(sea,dea);
return 0;
}
// 01008000 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);
if(op!=use) { OpUse(op,use); return 0; } // Use existing handler
OpStart(op,ea); Cycles=6;
if(ea >= 8) Cycles+=2;
EaCalc(10,0x3f, ea,0,1);
EaRead(10, 0, ea,0,0x3f,1);
// this is rewrite of Musashi's code
ot(" ldrb r2,[r7,#0x45]\n");
ot(" tst r2,#2\n");
ot(" mov r2,r0\n");
ot(" addne r2,r0,#0x01000000 ;@ add X\n");
ot(" rsbs r1,r2,#0x9a000000 ;@ do arithmetic\n");
ot(" bic r9,r9,#0xb0000000 ;@ clear all flags, except Z\n");
ot(" orrmi r9,r9,#0x80000000 ;@ N\n");
ot(" cmp r1,#0x9a000000\n");
ot(" beq finish%.4x\n",op);
ot("\n");
ot(" mvn r3,r9,lsr #3 ;@ Undefined V behavior\n",op);
ot(" and r2,r1,#0x0f000000\n");
ot(" cmp r2,#0x0a000000\n");
ot(" andeq r1,r1,#0xf0000000\n");
ot(" addeq r1,r1,#0x10000000\n");
ot(" and r3,r3,r1,lsr #3 ;@ Undefined V behavior part II\n",op);
ot(" tst r1,r1\n");
ot(" orr r9,r9,r3 ;@ save V\n",op);
ot(" bicne r9,r9,#0x40000000 ;@ Z\n");
ot(" orr r9,r9,#0x20000000 ;@ C\n");
ot("\n");
EaWrite(10, 1, ea,0,0x3f,1);
ot("finish%.4x%s\n",op,ms?"":":");
ot(" mov r2,r9,lsr #28\n");
ot(" strb r2, [r7,#0x45]\n");
OpEnd(ea);
return 0;
}
// --------------------- 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;
// 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);
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;
// must calculate reg EA first, because of situations like: suba.w (A0)+, A0
EaCalc (10,0x0e00, dea,2,1);
EaRead (10, 11, dea,2,0x0e00);
EaCalc ( 0,0x003f, sea,size);
EaRead ( 0, 0, sea,size,0x003f);
if (type==0) ot(" sub r11,r11,r0\n");
if (type==1) ot(" cmp r11,r0 ;@ Defines NZCV\n");
if (type==1) OpGetFlags(1,0); // Get Cmp flags
if (type==2) ot(" add r11,r11,r0\n");
ot("\n");
if (type!=1) EaWrite(10, 11, dea,2,0x0e00,1);
OpEnd(sea);
return 0;
}
// --------------------- Opcodes 0x9100+ ---------------------
// Emit a Subx/Addx opcode, 1t01ddd1 zz00rsss addx.z Ds,Dd
int OpAddx(int op)
{
int use=0;
int type=0,size=0,dea=0,sea=0,mem=0;
type=(op>>12)&5;
dea =(op>> 9)&7;
size=(op>> 6)&3; if (size>=3) return 1;
sea = op&7;
mem =(op>> 3)&1;
// See if we can do this opcode:
if (EaCanRead(sea,size)==0) return 1;
if (EaCanWrite(dea)==0) return 1;
if(mem) { sea+=0x20; dea+=0x20; }
use=op&~0x0e07; // Use same opcode for Dn
if (size==0&&(sea==0x27||dea==0x27)) use=op; // ___x.b -(a7)
if (op!=use) { OpUse(op,use); return 0; } // Use existing handler
OpStart(op,sea,dea); Cycles=4;
if(size>=2) Cycles+=4;
if(sea>=0x10) Cycles+=2;
ot(";@ Get r10=EA r11=EA value\n");
EaCalc( 0,0x0007,sea,size,1);
EaRead( 0, 11,sea,size,0x0007,1);
ot(";@ Get r0=Register r1=Register value\n");
EaCalc( 0,0x0e00,dea,size,1);
EaRead( 0, 1,dea,size,0x0e00,1);
ot(";@ Do arithmetic:\n");
GetXBit(type==1);
if (type==5 && size<2)
{
ot(";@ Make sure the carry bit will tip the balance:\n");
ot(" mvn r2,#0\n");
ot(" orr r11,r11,r2,lsr #%i\n",(size==0)?8:16);
ot("\n");
}
if (type==1) ot(" sbcs r1,r1,r11\n");
if (type==5) ot(" adcs r1,r1,r11\n");
ot(" orr r3,r9,#0xb0000000 ;@ for old Z\n");
OpGetFlags(type==1,1,0); // subtract
if (size<2) {
ot(" movs r2,r1,lsr #%i\n", size?16:24);
ot(" orreq r9,r9,#0x40000000 ;@ add potentially missed Z\n");
}
ot(" andeq r9,r9,r3 ;@ fix Z\n");
ot("\n");
ot(";@ Save result:\n");
EaWrite( 0, 1, dea,size,0x0e00,1);
OpEnd(sea,dea);
return 0;
}
// --------------------- Opcodes 0xb000+ ---------------------
// Emit a Cmp/Eor opcode, 1011rrrt xxeeeeee (rrr=Dn, t=cmp/eor, xx=size extension, eeeeee=ea)
int OpCmpEor(int op)
{
int rea=0,eor=0;
int size=0,ea=0,use=0;
// Get EA and register EA
rea=(op>>9)&7;
eor=(op>>8)&1;
size=(op>>6)&3; if (size>=3) return 1;
ea=op&0x3f;
if (eor && (ea>>3) == 1) return 1; // not a valid mode for eor
// See if we can do this opcode:
if (EaCanRead(ea,size)==0) return 1;
if (eor && EaCanWrite(ea)==0) return 1;
if (EaAn(ea)&&(eor||size==0)) return 1;
use=OpBase(op);
use&=~0x0e00; // Use 1 handler for register d0-7
if (op!=use) { OpUse(op,use); return 0; } // Use existing handler
OpStart(op,ea); Cycles=4;
if(eor) {
if(ea>8) Cycles+=4;
if(size>=2) Cycles+=4;
} else {
if(size>=2) Cycles+=2;
}
ot(";@ Get EA into r10 and value into r0:\n");
EaCalc (10,0x003f, ea,size,1);
EaRead (10, 0, ea,size,0x003f,1);
ot(";@ Get register operand into r1:\n");
EaCalc (1, 0x0e00, rea,size,1);
EaRead (1, 1, rea,size,0x0e00,1);
ot(";@ Do arithmetic:\n");
if (eor==0) ot(" cmp r1,r0\n");
if (eor)
{
ot(" eor r1,r0,r1\n");
ot(" adds r1,r1,#0 ;@ Defines NZ, clears CV\n");
}
OpGetFlags(eor==0,0); // Cmp like subtract
ot("\n");
if (eor) EaWrite(10, 1,ea,size,0x003f,1);
OpEnd(ea);
return 0;
}
// Emit a Cmpm opcode, 1011ddd1 xx001sss (rrr=Adst, xx=size extension, sss=Asrc)
int OpCmpm(int op)
{
int size=0,sea=0,dea=0,use=0;
// get size, get EAs
size=(op>>6)&3; if (size>=3) return 1;
sea=(op&7)|0x18;
dea=(op>>9)&0x3f;
use=op&~0x0e07; // Use 1 handler for all registers..
if (size==0&&(sea==0x1f||dea==0x1f)) use=op; // ..except (a7)+
if (op!=use) { OpUse(op,use); return 0; } // Use existing handler
OpStart(op,sea); Cycles=4;
ot(";@ Get src operand into r10:\n");
EaCalc (0,0x000f, sea,size,1);
EaRead (0, 10, sea,size,0x000f,1);
ot(";@ Get dst operand into r0:\n");
EaCalc (0,0x1e00, dea,size,1);
EaRead (0, 0, dea,size,0x1e00,1);
ot(" cmp r0,r10\n");
OpGetFlags(1,0); // Cmp like subtract
OpEnd(sea);
return 0;
}
// Emit a Chk opcode, 0100ddd1 x0eeeeee (rrr=Dn, x=size extension, eeeeee=ea)
int OpChk(int op)
{
int rea=0;
int size=0,ea=0,use=0;
// Get EA and register EA
rea=(op>>9)&7;
if((op>>7)&1)
size=1; // word operation
else size=2; // long
ea=op&0x3f;
if (EaAn(ea)) return 1; // not a valid mode
if (size!=1) return 1; // 000 variant only supports word
// See if we can do this opcode:
if (EaCanRead(ea,size)==0) return 1;
use=OpBase(op);
use&=~0x0e00; // Use 1 handler for register d0-7
if (op!=use) { OpUse(op,use); return 0; } // Use existing handler
OpStart(op,ea); Cycles=10;
ot(";@ Get EA into r10 and value into r0:\n");
EaCalc (10,0x003f, ea,size,1);
EaRead (10, 0, ea,size,0x003f,1);
ot(";@ Get register operand into r1:\n");
EaCalc (1, 0x0e00, rea,size,1);
EaRead (1, 1, rea,size,0x0e00,1);
ot(";@ get flags, including undocumented ones\n");
ot(" and r3,r9,#0x80000000\n");
ot(" adds r1,r1,#0 ;@ Defines NZ, clears CV\n");
OpGetFlags(0,0);
ot(";@ is reg negative?\n");
ot(" bmi chktrap%.4x\n",op);
ot(";@ Do arithmetic:\n");
ot(" cmp r1,r0\n");
ot(" bicgt r9,r9,#0x80000000 ;@ N\n");
ot(" bgt chktrap%.4x\n",op);
ot(";@ old N remains\n");
ot(" bic r9,r9,#0x80000000 ;@ N\n");
ot(" orr r9,r9,r3\n");
OpEnd(ea);
ot("chktrap%.4x%s ;@ CHK exception:\n",op,ms?"":":");
ot(" mov r0,#0x18\n");
ot(" bl Exception\n");
Cycles+=40;
OpEnd(ea);
return 0;
}
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