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Added the PDP-10's four arithmetic flags along with a negate() function -- the first of our functions that actually needs to set those flags

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Jeff 2017-03-01 17:23:54 -08:00 • committed by Jeff Parsons
commit 202374dd09
6 changed files with 417 additions and 283 deletions
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12
modules/pdp10/lib/defines.js
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@ -102,8 +102,16 @@ var PDP10 = {
DATA_LIMIT: Math.pow(2, 36),
WORD_SHIFT: Math.pow(2, 18),
WORD_MASK: 0o777777,
MAX_POS18: Math.pow(2, 17) - 1,
MAX_POS: Math.pow(2, 35) - 1,
/*
* 18-bit and 36-bit largest positive (and smallest negative) values; however, since we store all
* values as unsigned quantities, these are the unsigned equivalents.
*/
MAX_POS18: Math.pow(2, 17) - 1, // 131,071 (377777)
MIN_NEG18: Math.pow(2, 17), // -131,072 (400000)
MAX_POS36: Math.pow(2, 35) - 1, // 34,359,738,367 (377777 777777)
MIN_NEG36: Math.pow(2, 35), // -34,359,738,368 (400000 000000)
TWO_POW36: Math.pow(2, 36), // the two's complement of a 36-bit value is (value? TWO_POW36 - value : 0)
/*
* PDP-10 opcodes are 36-bit values, most of which use the following layout: