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Added the ^L MACRO-10 unary zero-bit-counting operator, and updated the last blog post with expression parser differences (eg, interpretation of numbers with a decimal point)

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Jeff 2017-03-21 17:40:37 -07:00 • committed by Jeff Parsons
commit 6ad35d2d17
2 changed files with 24 additions and 6 deletions
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9
_posts/2017-03-21-the-macro-10-assembler-50-years-later.md
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@ -183,17 +183,24 @@ Use double-quotes for ASCII constants and single-quotes for SIXBIT constants:
NOTE: When using the PCjs debugger, the constant must be preceded by an arithmetic operator (eg, '+'), otherwise it interprets
the quoted argument as a string. This is an idiosyncrasy of the "print" command, not the expression parser.
All MACRO-10 logical and arithmetic operators are supported, including:
Most MACRO-10 logical and arithmetic operators are supported, including:
- Unary arithmetic operators (+ and -)
- Unary complement operator (^-, aliased to ~)
- Unary base overrides (^D, ^O, and ^B)
- Unary zero-bit-count operator (^L)
- Binary shifting (B) and underscore shifting (_) operators
- Logical binary operations (! for OR, ^! for XOR, and & for AND)
- Multiplication and division (* and /)
- Addition and subtraction (+ and -)
- Angle brackets for expression grouping (< and >)
Unfortunately, since the PCjs expression parser predates MACRO-10 support, there are bound to be differences that I
haven't ironed out yet. One known difference involves numeric constants with a trailing period (decimal point): PCjs
historically treats such constants as decimal *integers*, whereas MACRO-10 treats numeric constants with either a
leading, embedded, or trailing period as a decimal *floating-point* number. I've chosen to ignore this difference for
now, since I'm holding off on all floating-point support for as long as possible.
Much more work is needed to make the MACRO-10 "Mini-Assembler" a general-purpose assembler, but it's already proved itself
useful in assembling the following tests:

21
modules/shared/lib/debugger.js
View file

@ -684,6 +684,10 @@ class Debugger extends Component
nUnary = (nUnary << 2) | 2;
continue;
}
if (sOp == '^L') {
nUnary = (nUnary << 2) | 3;
continue;
}
}
fError = true;
break;
@ -861,7 +865,7 @@ class Debugger extends Component
*
* WARNING: Whenever you make changes to this RegExp, make sure you update aBinOpPrecedence as needed, too.
*/
var regExp = /(\{|}|\|\||&&|\||\^!|\^B|\^O|\^D|\^-|~|\^_|_|&|!=|!|==|>=|>>>|>>|>|<=|<<|<|-|\+|%|\/|\*)/;
var regExp = /(\{|}|\|\||&&|\||\^!|\^B|\^O|\^D|\^L|\^-|~|\^_|_|&|!=|!|==|>=|>>>|>>|>|<=|<<|<|-|\+|%|\/|\*)/;
sExp = sExp.replace(/(^|[^A-Z0-9$%.])([0-9]+)B/, "$1$2^_");
var asValues = sExp.split(regExp);
value = this.parseArray(asValues, 0, asValues.length, this.nBase, fQuiet);
@ -965,7 +969,7 @@ class Debugger extends Component
* @param {string|undefined} sValue
* @param {string|null} [sName] is the name of the value, if any
* @param {boolean} [fQuiet]
* @param {number} [nUnary] (0 for none, 1 for negate, 2 for complement)
* @param {number} [nUnary] (0 for none, 1 for negate, 2 for complement, 3 for leading zeros)
* @return {number|undefined} numeric value, or undefined if sValue is either undefined or invalid
*/
parseValue(sValue, sName, fQuiet, nUnary = 0)
@ -986,11 +990,18 @@ class Debugger extends Component
}
if (value != null) {
while (nUnary) {
if (nUnary & 1) {
switch(nUnary & 0o3) {
case 1:
value = -this.truncate(value);
}
else if (nUnary & 2) {
break;
case 2:
value = this.evalXOR(value, -1); // this is easier than adding an evalNOT()...
break;
case 3:
var bit = 35; // simple left-to-right zero-bit-counting loop...
while (bit >= 0 && !this.evalAND(value, Math.pow(2, bit))) bit--;
value = 35 - bit;
break;
}
nUnary >>>= 2;
}