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Fixed the Debugger's arithmetic truncation function (truncate())

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This commit is contained in:
Jeff 2017-04-01 14:36:39 -07:00 • committed by Jeff Parsons
commit 75b9a9c2ba
9 changed files with 84 additions and 149 deletions
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9
modules/pdp10/lib/debugger.js
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@ -519,7 +519,14 @@ class DebuggerPDP10 extends Debugger {
*/
evalMUL(dst, src)
{
/*
* The CPU requires that all 36-bit inputs/outputs be UNSIGNED, whereas our expression evaluator allows signed
* inputs/outputs. So we perform two's complement conversions on all inputs/outputs as needed.
*/
if (dst < 0) dst += PDP10.WORD_LIMIT;
if (src < 0) src += PDP10.WORD_LIMIT;
var result = PDP10.doMUL.call(this.cpu, dst, src, false, true);
if (result >= PDP10.INT_LIMIT) result -= PDP10.WORD_LIMIT;
if (MAXDEBUG) {
var resultJS = this.truncate(dst * src);
if (resultJS !== result) {
@ -3932,7 +3939,7 @@ class DebuggerPDP10 extends Debugger {
*/
doTest()
{
if (DEBUG) {
if (MAXDEBUG) {
var ops = {}, aOpXXX = [];
var op, opXXX, opCode, sOperation;
for (op = 0o00000; op <= 0o77774; op += 4) {

22
modules/shared/lib/debugger.js
View file

@ -473,15 +473,21 @@ class Debugger extends Component
}
else {
if (nBits <= 32) {
vNew = v | 0;
} else {
vNew = (v << (32 - nBits)) >> (32 - nBits);
}
else {
limit = Math.pow(2, nBits - 1);
if (v < -limit) {
if (v < -limit * 2) vNew = v % (limit * 2);
vNew += (limit * 2);
} else if (vNew >= limit) {
if (v >= limit * 2) vNew = v % (limit * 2);
vNew -= (limit * 2); // the sign bit was set in this overly large value, so make it negative
if (v >= limit) {
vNew = (v % limit);
if (((v / limit)|0) & 1) vNew -= limit;
} else if (v < -limit) {
vNew = (v % limit);
if ((((-v - 1) / limit) | 0) & 1) {
if (vNew) vNew += limit;
}
else {
if (!vNew) vNew -= limit;
}
}
}
}