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Implemented branches and RTS

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This commit is contained in:
Jeff 2016-09-26 11:27:32 -07:00 • committed by Jeff Parsons
commit 6af956b8f0
8 changed files with 1932 additions and 1922 deletions
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48
modules/pdp11/lib/cpustate.js
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@ -125,7 +125,7 @@ CPUStatePDP11.prototype.initRegs = function()
/*
* TODO: Verify the initial state of all PDP-11 flags and registers (are they well-documented?)
*/
this.flagC = 0x10000; // PSW C bit
this.flagC = 0x10000; // PSW C bit
this.flagV = 0x8000; // PSW V bit
this.flagZ = 0xffff; // ~ PSW Z bit (TODO: Why do we clear instead of set Z, like other flags?)
this.flagN = 0x8000; // PSW N bit
@ -1469,21 +1469,15 @@ CPUStatePDP11.prototype.writeByteByMode = function(addressMode, data, writeFlags
};
/**
* branch(PC, instruction)
* branch(opCode)
*
* @this {CPUStatePDP11}
* @param {number} PC
* @param {number} instruction
* @return {number}
* @param {number} opCode
* @return {number} (PC +/- the word delta specified in the opCode)
*/
CPUStatePDP11.prototype.branch = function(PC, instruction)
CPUStatePDP11.prototype.branch = function(opCode)
{
if (instruction & 0x80) { /*0200*/
instruction |= 0xff00;
} else {
instruction &= 0xff;
}
return ((instruction << 1) + PC) & 0xffff;
return (this.regsGen[PDP11.REG.PC] + ((opCode << 24) >> 23)) & 0xffff;
};
/**
@ -1972,70 +1966,70 @@ CPUStatePDP11.prototype.stepCPU = function(nMinCycles)
// switch (opCode & 0xFF00) /*0177400*/ { // Program control instructions & traps
// case 0x100: /*0000400*/ // BR
// //LOG_INSTRUCTION(opCode, 4, "BR");
// this.regsGen[7] = this.branch(this.regsGen[7], opCode);
// this.regsGen[7] = this.branch(opCode);
// break;
// case 0x200: /*0001000*/ // BNE
// //LOG_INSTRUCTION(opCode, 4, "BNE");
// if (this.flagZ & 0xffff) this.regsGen[7] = this.branch(this.regsGen[7], opCode);
// if (this.flagZ & 0xffff) this.regsGen[7] = this.branch(opCode);
// break;
// case 0x300: /*0001400*/ // BEQ
// //LOG_INSTRUCTION(opCode, 4, "BEQ");
// if (!(this.flagZ & 0xffff)) this.regsGen[7] = this.branch(this.regsGen[7], opCode);
// if (!(this.flagZ & 0xffff)) this.regsGen[7] = this.branch(opCode);
// break;
// case 0x400: /*0002000*/ // BGE
// //LOG_INSTRUCTION(opCode, 4, "BGE");
// if ((this.flagN & 0x8000) ===
// (this.flagV & 0x8000)) this.regsGen[7] = this.branch(this.regsGen[7], opCode);
// (this.flagV & 0x8000)) this.regsGen[7] = this.branch(opCode);
// break;
// case 0x500: /*0002400*/ // BLT
// //LOG_INSTRUCTION(opCode, 4, "BLT");
// if ((this.flagN & 0x8000) !==
// (this.flagV & 0x8000)) this.regsGen[7] = this.branch(this.regsGen[7], opCode);
// (this.flagV & 0x8000)) this.regsGen[7] = this.branch(opCode);
// break;
// case 0x600: /*0003000*/ // BGT
// //LOG_INSTRUCTION(opCode, 4, "BGT");
// if ((this.flagZ & 0xffff) && ((this.flagN & 0x8000) ===
// (this.flagV & 0x8000))) this.regsGen[7] = this.branch(this.regsGen[7], opCode);
// (this.flagV & 0x8000))) this.regsGen[7] = this.branch(opCode);
// break;
// case 0x700: /*0003400*/ // BLE
// //LOG_INSTRUCTION(opCode, 4, "BLE");
// if (!(this.flagZ & 0xffff) || ((this.flagN & 0x8000) !==
// (this.flagV & 0x8000))) this.regsGen[7] = this.branch(this.regsGen[7], opCode);
// (this.flagV & 0x8000))) this.regsGen[7] = this.branch(opCode);
// break;
// case 0x8000: /*0100000*/ // BPL
// //LOG_INSTRUCTION(opCode, 4, "BPL");
// if (!(this.flagN & 0x8000)) this.regsGen[7] = this.branch(this.regsGen[7], opCode);
// if (!(this.flagN & 0x8000)) this.regsGen[7] = this.branch(opCode);
// break;
// case 0x8200: /*0101000*/ // BHI
// //LOG_INSTRUCTION(opCode, 4, "BHI");
// if (!(this.flagC & 0x10000) &&
// (this.flagZ & 0xffff)) this.regsGen[7] = this.branch(this.regsGen[7], opCode);
// (this.flagZ & 0xffff)) this.regsGen[7] = this.branch(opCode);
// break;
// case 0x8100: /*0100400*/ // BMI
// //LOG_INSTRUCTION(opCode, 4, "BMI");
// if ((this.flagN & 0x8000)) this.regsGen[7] = this.branch(this.regsGen[7], opCode);
// if ((this.flagN & 0x8000)) this.regsGen[7] = this.branch(opCode);
// break;
// case 0x8300: /*0101400*/ // BLOS
// //LOG_INSTRUCTION(opCode, 4, "BLOS");
// if ((this.flagC & 0x10000) ||
// !(this.flagZ & 0xffff)) this.regsGen[7] = this.branch(this.regsGen[7], opCode);
// !(this.flagZ & 0xffff)) this.regsGen[7] = this.branch(opCode);
// break;
// case 0x8400: /*0102000*/ // BVC
// //LOG_INSTRUCTION(opCode, 4, "BVC");
// if (!(this.flagV & 0x8000)) this.regsGen[7] = this.branch(this.regsGen[7], opCode);
// if (!(this.flagV & 0x8000)) this.regsGen[7] = this.branch(opCode);
// break;
// case 0x8500: /*0102400*/ // BVS
// //LOG_INSTRUCTION(opCode, 4, "BVS");
// if ((this.flagV & 0x8000)) this.regsGen[7] = this.branch(this.regsGen[7], opCode);
// if ((this.flagV & 0x8000)) this.regsGen[7] = this.branch(opCode);
// break;
// case 0x8600: /*0103000*/ // BCC
// //LOG_INSTRUCTION(opCode, 4, "BCC");
// if (!(this.flagC &
// 0x10000)) this.regsGen[7] = this.branch(this.regsGen[7], opCode);
// 0x10000)) this.regsGen[7] = this.branch(opCode);
// break;
// case 0x8700: /*0103400*/ // BCS
// //LOG_INSTRUCTION(opCode, 4, "BCS");
// if (this.flagC & 0x10000) this.regsGen[7] = this.branch(this.regsGen[7], opCode);
// if (this.flagC & 0x10000) this.regsGen[7] = this.branch(opCode);
// break;
// case 0x8800: /*0104000*/ // EMT 104000 -> 104377
// //LOG_INSTRUCTION(opCode, 7, "EMT");