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https://github.com/RaySollium99/picodrive.git
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code review and optimizations
git-svn-id: file:///home/notaz/opt/svn/PicoDrive@180 be3aeb3a-fb24-0410-a615-afba39da0efa
This commit is contained in:
notaz
parent
3a5e6cf847
commit
85a36a57a8
10 changed files with 540 additions and 364 deletions
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@ -139,8 +139,8 @@ int OpUnlk(int op)
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OpStart(op,0x10);
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ot(";@ Get An\n");
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EaCalc(10, 7, 8, 2, 1);
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EaRead(10, 0, 8, 2, 7, 1);
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EaCalc(10, 0xf, 8, 2, 1);
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EaRead(10, 0, 8, 2, 0xf, 1);
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ot(" add r11,r0,#4 ;@ A7+=4\n");
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ot("\n");
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@ -151,7 +151,7 @@ int OpUnlk(int op)
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ot("\n");
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ot(";@ An = value from stack:\n");
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EaWrite(10, 0, 8, 2, 7, 1);
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Cycles=12;
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OpEnd(0x10);
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return 0;
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@ -181,7 +181,6 @@ int Op4E70(int op)
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SuperChange(op);
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CheckInterrupt(op);
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OpEnd(0x10);
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SuperEnd(op);
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return 0;
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case 5: // rts
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@ -225,7 +224,7 @@ int OpJsr(int op)
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// See if we can do this opcode:
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if (EaCanRead(sea,-1)==0) return 1;
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use=OpBase(op);
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use=OpBase(op,0);
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if (op!=use) { OpUse(op,use); return 0; } // Use existing handler
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OpStart(op,(op&0x40)?0:0x10);
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@ -294,17 +293,17 @@ int OpDbra(int op)
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break;
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case 2: // hi
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ot(" tst r9,#0x60000000 ;@ hi: !C && !Z\n");
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ot(" beq DbraTrue%.4x\n\n",op);
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ot(" beq DbraTrue\n\n");
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break;
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case 3: // ls
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ot(" tst r9,#0x60000000 ;@ ls: C || Z\n");
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ot(" bne DbraTrue%.4x\n\n",op);
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ot(" bne DbraTrue\n\n");
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break;
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default:
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ot(";@ Is the condition true?\n");
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ot(" msr cpsr_flg,r9 ;@ ARM flags = 68000 flags\n");
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ot(";@ If so, don't dbra\n");
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ot(" b%s DbraTrue%.4x\n\n",Cond[cc],op);
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ot(" b%s DbraTrue\n\n",Cond[cc]);
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break;
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}
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@ -332,10 +331,11 @@ int OpDbra(int op)
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OpEnd();
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}
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if (cc==0||cc>=2)
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//if (cc==0||cc>=2)
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if (op==0x50c8)
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{
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ot(";@ condition true:\n");
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ot("DbraTrue%.4x%s\n", op, ms?"":":");
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ot("DbraTrue%s\n", ms?"":":");
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ot(" add r4,r4,#2 ;@ Skip branch offset\n");
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ot("\n");
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Cycles=12;
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@ -352,6 +352,7 @@ int OpBranch(int op)
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int size=0,use=0;
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int offset=0;
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int cc=0;
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char *asr_r11="";
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offset=(char)(op&0xff);
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cc=(op>>8)&15;
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@ -365,33 +366,48 @@ int OpBranch(int op)
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if (op!=use) { OpUse(op,use); return 0; } // Use existing handler
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OpStart(op,size?0x10:0);
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ot(";@ Get Branch offset:\n");
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if (size)
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{
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EaCalc(0,0,0x3c,size);
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EaRead(0,0,0x3c,size,0);
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}
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else
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ot(" mov r0,r8,asl #24 ;@ Shift 8-bit signed offset up...\n\n");
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// above code messes cycles
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Cycles=10; // Assume branch taken
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if (cc==1) ot(" ldr r10,[r7,#0x60] ;@ Get Memory base\n");
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if (cc>=2)
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switch (cc)
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{
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ot(";@ Is the condition true?\n");
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if ((cc&~1)==2) ot(" eor r9,r9,#0x20000000 ;@ Invert carry for hi/ls\n");
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ot(" msr cpsr_flg,r9 ;@ ARM flags = 68000 flags\n");
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if ((cc&~1)==2) ot(" eor r9,r9,#0x20000000\n");
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ot(" b%s DontBranch%.4x\n",Cond[cc^1],op);
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ot("\n");
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case 0: // T
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case 1: // F
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break;
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case 2: // hi
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ot(" tst r9,#0x60000000 ;@ hi: !C && !Z\n");
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ot(" bne BccDontBranch%i\n\n",8<<size);
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break;
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case 3: // ls
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ot(" tst r9,#0x60000000 ;@ ls: C || Z\n");
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ot(" beq BccDontBranch%i\n\n",8<<size);
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break;
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default:
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ot(";@ Is the condition true?\n");
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ot(" msr cpsr_flg,r9 ;@ ARM flags = 68000 flags\n");
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ot(" b%s BccDontBranch%i\n\n",Cond[cc^1],8<<size);
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break;
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}
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if (size==0) ot(" mov r0,r0,asr #24 ;@ ...shift down\n\n");
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if (size)
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{
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if (size<2)
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{
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ot(" ldrsh r11,[r4] ;@ Fetch Branch offset\n");
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}
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else
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{
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ot(" ldrh r2,[r4] ;@ Fetch Branch offset\n");
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ot(" ldrh r11,[r4,#2]\n");
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ot(" orr r11,r11,r2,lsl #16\n");
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}
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}
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else
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{
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ot(" mov r11,r8,asl #24 ;@ Shift 8-bit signed offset up...\n\n");
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asr_r11=",asr #24";
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}
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ot(";@ Branch taken - Add on r0 to PC\n");
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@ -399,12 +415,11 @@ int OpBranch(int op)
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{
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ot(";@ Bsr - remember old PC\n");
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ot(" sub r1,r4,r10 ;@ r1 = Old PC\n");
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if (size) ot(" add r1,r1,#%d\n",1<<size);
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ot(" mov r1,r1, lsl #8\n");
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ot(" ldr r2,[r7,#0x3c]\n");
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ot(" mov r1,r1, asr #8\n");
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ot("\n");
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if (size) ot(" sub r4,r4,#%d ;@ (Branch is relative to Opcode+2)\n",1<<size);
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ot(" ldr r2,[r7,#0x3c]\n");
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ot(" add r4,r4,r0 ;@ r4 = New PC\n");
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ot(";@ Push r1 onto stack\n");
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ot(" sub r0,r2,#4 ;@ Predecrement A7\n");
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ot(" str r0,[r7,#0x3c] ;@ Save A7\n");
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@ -414,33 +429,36 @@ int OpBranch(int op)
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if (offset==0 || offset==-1)
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{
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ot(";@ Branch is quite far, so may be a good idea to check Memory Base+pc\n");
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CheckPc(4);
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ot(" add r0,r4,r11%s ;@ r4 = New PC\n",asr_r11);
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CheckPc(0);
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}
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else
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ot(" add r4,r4,r11%s ;@ r4 = New PC\n",asr_r11);
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}
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else
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{
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if (size) ot(" sub r4,r4,#%d ;@ (Branch is relative to Opcode+2)\n",1<<size);
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if (offset==0 || offset==-1)
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{
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ot(" add r0,r4,r0 ;@ r4 = New PC\n");
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ot(" add r0,r4,r11%s ;@ r4 = New PC\n",asr_r11);
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ot(";@ Branch is quite far, so may be a good idea to check Memory Base+pc\n");
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CheckPc(0);
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}
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else
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{
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ot(" add r4,r4,r0 ;@ r4 = New PC\n");
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ot(" add r4,r4,r11%s ;@ r4 = New PC\n",asr_r11);
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ot("\n");
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}
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}
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OpEnd(size?0x10:0);
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if (cc>=2)
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// since all "DontBranch" code is same for every size, output only once
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if (cc>=2&&(op&0xff00)==0x6200)
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{
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ot("DontBranch%.4x%s\n", op, ms?"":":");
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Cycles+=(size==1)? 2 : -2; // Branch not taken
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OpEnd(size?0x10:0);
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ot("BccDontBranch%i%s\n", 8<<size, ms?"":":");
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if (size) ot(" add r4,r4,#%d\n",8<<size);
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Cycles+=(size==1) ? 2 : -2; // Branch not taken
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OpEnd(0);
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}
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return 0;
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