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Fixed some cycle calculation problems involving src and dst decoding (eg, when the dst operand is only being read, not written)

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This commit is contained in:
Jeff 2016-10-03 15:31:01 -07:00 • committed by Jeff Parsons
commit bdc946a62d
1 changed files with 70 additions and 25 deletions
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95
modules/pdp11/lib/cpuops.js
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@ -497,6 +497,10 @@ PDP11.opADD = function(opCode)
*/ */
PDP11.opASH = function(opCode) PDP11.opASH = function(opCode)
{ {
/*
* NOTE: Because readWordByMode() is being used to READ (not WRITE) the DSTMODE field of opCode,
* the srcMode and srcReg properties will be updated instead of the dstMode and dstReg properties.
*/
var src = this.readWordByMode(opCode); var src = this.readWordByMode(opCode);
var reg = (opCode >> 6) & 7; var reg = (opCode >> 6) & 7;
var result = this.regsGen[reg]; var result = this.regsGen[reg];
@ -521,7 +525,7 @@ PDP11.opASH = function(opCode)
} }
this.regsGen[reg] = result & 0xffff; this.regsGen[reg] = result & 0xffff;
this.flagN = this.flagZ = result; this.flagN = this.flagZ = result;
this.nStepCycles -= (this.dstMode? (5 + 1) : (6 + 1)) + src; this.nStepCycles -= (this.srcMode? (5 + 1) : (6 + 1)) + src;
}; };
/** /**
@ -532,6 +536,10 @@ PDP11.opASH = function(opCode)
*/ */
PDP11.opASHC = function(opCode) PDP11.opASHC = function(opCode)
{ {
/*
* NOTE: Because readWordByMode() is being used to READ (not WRITE) the DSTMODE field of opCode,
* the srcMode and srcReg properties will be updated instead of the dstMode and dstReg properties.
*/
var src = this.readWordByMode(opCode); var src = this.readWordByMode(opCode);
var reg = (opCode >> 6) & 7; var reg = (opCode >> 6) & 7;
var dst = (this.regsGen[reg] << 16) | this.regsGen[reg | 1]; var dst = (this.regsGen[reg] << 16) | this.regsGen[reg | 1];
@ -563,7 +571,7 @@ PDP11.opASHC = function(opCode)
this.regsGen[reg | 1] = result & 0xffff; this.regsGen[reg | 1] = result & 0xffff;
this.flagN = result >> 16; this.flagN = result >> 16;
this.flagZ = result >> 16 | result; this.flagZ = result >> 16 | result;
this.nStepCycles -= (this.dstMode? (5 + 1) : (6 + 1)) + src; this.nStepCycles -= (this.srcMode? (5 + 1) : (6 + 1)) + src;
}; };
/** /**
@ -692,8 +700,15 @@ PDP11.opBISB = function(opCode)
*/ */
PDP11.opBIT = function(opCode) PDP11.opBIT = function(opCode)
{ {
this.updateNZVFlags(this.readWordByMode(opCode >> PDP11.SRCMODE.SHIFT) & this.readWordByMode(opCode)); /*
this.nStepCycles -= (this.dstMode? (3 + 1) + (this.srcReg && this.dstReg >= 6? 1 : 0) : (this.srcMode? (3 + 1) : (2 + 1)) + (this.dstReg == 7? 2 : 0)); * NOTE: Because readWordByMode() is being used to READ (not WRITE) the DSTMODE field of opCode,
* the srcMode and srcReg properties need to be copied before we READ the SRCMODE field of opCode.
*/
var dst = this.readWordByMode(opCode);
var dstMode = this.srcMode;
var dstReg = this.srcReg;
this.updateNZVFlags(this.readWordByMode(opCode >> PDP11.SRCMODE.SHIFT) & dst);
this.nStepCycles -= (dstMode? (3 + 1) + (this.srcReg && dstReg >= 6? 1 : 0) : (this.srcMode? (3 + 1) : (2 + 1)) + (dstReg == 7? 2 : 0));
}; };
/** /**
@ -704,8 +719,15 @@ PDP11.opBIT = function(opCode)
*/ */
PDP11.opBITB = function(opCode) PDP11.opBITB = function(opCode)
{ {
this.updateNZVFlags((this.readByteByMode(opCode >> PDP11.SRCMODE.SHIFT) & this.readByteByMode(opCode)) << 8); /*
this.nStepCycles -= (this.dstMode? (3 + 1) + (this.srcReg && this.dstReg >= 6? 1 : 0) : (this.srcMode? (3 + 1) : (2 + 1)) + (this.dstReg == 7? 2 : 0)); * NOTE: Because readByteByMode() is being used to READ (not WRITE) the DSTMODE field of opCode,
* the srcMode and srcReg properties need to be copied before we READ the SRCMODE field of opCode.
*/
var dst = this.readByteByMode(opCode);
var dstMode = this.srcMode;
var dstReg = this.srcReg;
this.updateNZVFlags((this.readByteByMode(opCode >> PDP11.SRCMODE.SHIFT) & dst) << 8);
this.nStepCycles -= (dstMode? (3 + 1) + (this.srcReg && dstReg >= 6? 1 : 0) : (this.srcMode? (3 + 1) : (2 + 1)) + (dstReg == 7? 2 : 0));
}; };
/** /**
@ -961,15 +983,21 @@ PDP11.opCLx = function(opCode)
*/ */
PDP11.opCMP = function(opCode) PDP11.opCMP = function(opCode)
{ {
var src = this.readWordByMode(opCode >> PDP11.SRCMODE.SHIFT); /*
* NOTE: Because readWordByMode() is being used to READ (not WRITE) the DSTMODE field of opCode,
* the srcMode and srcReg properties need to be copied before we READ the SRCMODE field of opCode.
*/
var dst = this.readWordByMode(opCode); var dst = this.readWordByMode(opCode);
var dstMode = this.srcMode;
var dstReg = this.srcReg;
var src = this.readWordByMode(opCode >> PDP11.SRCMODE.SHIFT);
var result = src - dst; var result = src - dst;
/* /*
* NOTE: CMP calculates (src - dst) rather than (dst - src), so when we call updateSubFlags(), * NOTE: CMP calculates (src - dst) rather than (dst - src), so when we call updateSubFlags(),
* we must reverse the order of the src and dst parameters. * we must reverse the order of the src and dst parameters.
*/ */
this.updateSubFlags(result, dst, src); this.updateSubFlags(result, dst, src);
this.nStepCycles -= (this.dstMode? (3 + 1) + (this.srcReg && this.dstReg >= 6? 1 : 0) : (this.srcMode? (3 + 1) : (2 + 1)) + (this.dstReg == 7? 2 : 0)); this.nStepCycles -= (dstMode? (3 + 1) + (this.srcReg && dstReg >= 6? 1 : 0) : (this.srcMode? (3 + 1) : (2 + 1)) + (dstReg == 7? 2 : 0));
}; };
/** /**
@ -980,15 +1008,21 @@ PDP11.opCMP = function(opCode)
*/ */
PDP11.opCMPB = function(opCode) PDP11.opCMPB = function(opCode)
{ {
var src = this.readByteByMode(opCode >> PDP11.SRCMODE.SHIFT) << 8; /*
* NOTE: Because readByteByMode() is being used to READ (not WRITE) the DSTMODE field of opCode,
* the srcMode and srcReg properties need to be copied before we READ the SRCMODE field of opCode.
*/
var dst = this.readByteByMode(opCode) << 8; var dst = this.readByteByMode(opCode) << 8;
var dstMode = this.srcMode;
var dstReg = this.srcReg;
var src = this.readByteByMode(opCode >> PDP11.SRCMODE.SHIFT) << 8;
var result = src - dst; var result = src - dst;
/* /*
* NOTE: CMP calculates (src - dst) rather than (dst - src), so when we call updateSubFlags(), * NOTE: CMP calculates (src - dst) rather than (dst - src), so when we call updateSubFlags(),
* we must reverse the order of the src and dst parameters. * we must reverse the order of the src and dst parameters.
*/ */
this.updateSubFlags(result, dst, src); this.updateSubFlags(result, dst, src);
this.nStepCycles -= (this.dstMode? (3 + 1) + (this.srcReg && this.dstReg >= 6? 1 : 0) : (this.srcMode? (3 + 1) : (2 + 1)) + (this.dstReg == 7? 2 : 0)); this.nStepCycles -= (dstMode? (3 + 1) + (this.srcReg && dstReg >= 6? 1 : 0) : (this.srcMode? (3 + 1) : (2 + 1)) + (dstReg == 7? 2 : 0));
}; };
/** /**
@ -1158,12 +1192,13 @@ PDP11.JMP_CYCLES = [
PDP11.opJMP = function(opCode) PDP11.opJMP = function(opCode)
{ {
/* /*
* Since JMP and JSR opcodes have their own unique timings for the various src and dst modes, we must snapshot * Since JMP and JSR opcodes have their own unique timings for the various dst modes, we must snapshot
* nStepCycles before decoding the modes, and then use that to update nStepCycles. * nStepCycles before decoding the mode, and then use that to update nStepCycles. Moreover, we must use
* srcMode rather than dstMode, because JMP does not WRITE the dst operand; it merely READs it.
*/ */
var nSnapCycles = this.nStepCycles; var nSnapCycles = this.nStepCycles;
this.setPC(this.getVirtualByMode(opCode, PDP11.ACCESS.VIRT)); this.setPC(this.getVirtualByMode(opCode, PDP11.ACCESS.VIRT));
this.nStepCycles = nSnapCycles - PDP11.JMP_CYCLES[this.dstMode]; this.nStepCycles = nSnapCycles - PDP11.JMP_CYCLES[this.srcMode];
}; };
PDP11.JSR_CYCLES = [ PDP11.JSR_CYCLES = [
@ -1179,8 +1214,9 @@ PDP11.JSR_CYCLES = [
PDP11.opJSR = function(opCode) PDP11.opJSR = function(opCode)
{ {
/* /*
* Since JMP and JSR opcodes have their own unique timings for the various src and dst modes, we must snapshot * Since JMP and JSR opcodes have their own unique timings for the various dst modes, we must snapshot
* nStepCycles before decoding the modes, and then use that to update nStepCycles. * nStepCycles before decoding the mode, and then use that to update nStepCycles. Moreover, we must use
* srcMode rather than dstMode, because JSR does not WRITE the dst operand; it merely READs it.
*/ */
var nSnapCycles = this.nStepCycles; var nSnapCycles = this.nStepCycles;
var addr = this.getVirtualByMode(opCode, PDP11.ACCESS.VIRT); var addr = this.getVirtualByMode(opCode, PDP11.ACCESS.VIRT);
@ -1188,7 +1224,7 @@ PDP11.opJSR = function(opCode)
this.pushWord(this.regsGen[reg]); this.pushWord(this.regsGen[reg]);
this.regsGen[reg] = this.getPC(); this.regsGen[reg] = this.getPC();
this.setPC(addr); this.setPC(addr);
this.nStepCycles = nSnapCycles - PDP11.JSR_CYCLES[this.dstMode]; this.nStepCycles = nSnapCycles - PDP11.JSR_CYCLES[this.srcMode];
}; };
/** /**
@ -1249,11 +1285,12 @@ PDP11.MOV_CYCLES = [
PDP11.opMOV = function(opCode) PDP11.opMOV = function(opCode)
{ {
/* /*
* Since MOV opcodes have their own unique timings for the various src and dst modes, we must snapshot * Since MOV opcodes have their own unique timings for the various dst modes, we must snapshot
* nStepCycles before decoding the modes, and then use that to update nStepCycles. * nStepCycles after decoding the src mode, and then use that to update nStepCycles.
*/ */
var data = this.readWordByMode(opCode >> PDP11.SRCMODE.SHIFT);
var nSnapCycles = this.nStepCycles; var nSnapCycles = this.nStepCycles;
this.updateNZVFlags(this.writeWordByMode(opCode, this.readWordByMode(opCode >> PDP11.SRCMODE.SHIFT))); this.updateNZVFlags(this.writeWordByMode(opCode, data));
this.nStepCycles = nSnapCycles - PDP11.MOV_CYCLES[(this.srcMode? 8 : 0) + this.dstMode] + (this.dstReg == 7 && !this.dstMode? 2 : 0); this.nStepCycles = nSnapCycles - PDP11.MOV_CYCLES[(this.srcMode? 8 : 0) + this.dstMode] + (this.dstReg == 7 && !this.dstMode? 2 : 0);
}; };
@ -1283,8 +1320,8 @@ PDP11.MTP_CYCLES = [
PDP11.opMTPD = function(opCode) PDP11.opMTPD = function(opCode)
{ {
/* /*
* Since MTPD and MTPI opcodes have their own unique timings for the various src and dst modes, we must snapshot * Since MTPD and MTPI opcodes have their own unique timings for the various dst modes, we must snapshot
* nStepCycles before decoding the modes, and then use that to update nStepCycles. * nStepCycles before decoding the mode, and then use that to update nStepCycles.
*/ */
var data = this.popWord(); var data = this.popWord();
var nSnapCycles = this.nStepCycles; var nSnapCycles = this.nStepCycles;
@ -1302,8 +1339,8 @@ PDP11.opMTPD = function(opCode)
PDP11.opMTPI = function(opCode) PDP11.opMTPI = function(opCode)
{ {
/* /*
* Since MTPD and MTPI opcodes have their own unique timings for the various src and dst modes, we must snapshot * Since MTPD and MTPI opcodes have their own unique timings for the various dst modes, we must snapshot
* nStepCycles before decoding the modes, and then use that to update nStepCycles. * nStepCycles before decoding the mode, and then use that to update nStepCycles.
*/ */
var data = this.popWord(); var data = this.popWord();
var nSnapCycles = this.nStepCycles; var nSnapCycles = this.nStepCycles;
@ -1659,10 +1696,14 @@ PDP11.opTRAP = function(opCode)
*/ */
PDP11.opTST = function(opCode) PDP11.opTST = function(opCode)
{ {
/*
* NOTE: Because readWordByMode() is being used to READ (not WRITE) the DSTMODE field of opCode,
* the srcMode and srcReg properties will be updated instead of the dstMode and dstReg properties.
*/
var result = this.readWordByMode(opCode); var result = this.readWordByMode(opCode);
this.assert(!(result & ~0xffff)); // assert that C flag will be clear this.assert(!(result & ~0xffff)); // assert that C flag will be clear
this.updateAllFlags(result); this.updateAllFlags(result);
this.nStepCycles -= (this.dstMode? (3 + 1) : (2 + 1) + (this.dstReg == 7? 2 : 0)); this.nStepCycles -= (this.srcMode? (3 + 1) : (2 + 1) + (this.srcReg == 7? 2 : 0));
}; };
/** /**
@ -1673,10 +1714,14 @@ PDP11.opTST = function(opCode)
*/ */
PDP11.opTSTB = function(opCode) PDP11.opTSTB = function(opCode)
{ {
/*
* NOTE: Because readByteByMode() is being used to READ (not WRITE) the DSTMODE field of opCode,
* the srcMode and srcReg properties will be updated instead of the dstMode and dstReg properties.
*/
var result = this.readByteByMode(opCode); var result = this.readByteByMode(opCode);
this.assert(!(result & ~0xff)); // assert that C flag will be clear this.assert(!(result & ~0xff)); // assert that C flag will be clear
this.updateAllFlags(result << 8); this.updateAllFlags(result << 8);
this.nStepCycles -= (this.dstMode? (3 + 1) : (2 + 1) + (this.dstReg == 7? 2 : 0)); this.nStepCycles -= (this.srcMode? (3 + 1) : (2 + 1) + (this.srcReg == 7? 2 : 0));
}; };
/** /**