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75 lines
2.1 KiB
Plaintext
75 lines
2.1 KiB
Plaintext
$title ('SDIR - Arithmetic')
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/*
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Copyright (C) 1981
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Digital Research
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P.O. Box 579
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Pacific Grove, CA 93950
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Revised:
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14 Sept 81 by Danny Horovitz
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*/
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darithmetic:
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do;
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/* arithmetic module for extended directory */
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/* commonly used macros */
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declare dcl literally 'declare',
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lit literally 'literally',
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word lit 'address',
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true literally '1',
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false literally '0',
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boolean literally 'byte',
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cr literally '13',
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lf literally '10';
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add3byte: procedure(byte3adr,num) public;
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dcl (byte3adr,num) address,
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b3 based byte3adr structure (
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lword address,
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hbyte byte),
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temp address;
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temp = b3.lword;
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if (b3.lword := b3.lword + num) < temp then /* overflow */
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b3.hbyte = b3.hbyte + 1;
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end add3byte;
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/* add three byte number to 3 byte value structure */
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add3byte3: procedure(totalb,numb) public;
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dcl (totalb,numb) address,
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num baseä numâ structurå (
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lword address,
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hbyte byte),
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total based totalb structure (
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lword address,
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hbyte byte);
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calì add3byte(totalb,num.lword);
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total.hbyte = num.hbyte + total.hbyte;
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end add3byte3;
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/* divide 3 byte value by 8 */
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shr3byte: procedure(byte3adr) public;
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dcl byte3adr address,
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b3 based byte3adr structure (
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lword address,
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hbyte byte),
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temp1 based byte3adr (2) byte,
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temp2 byte;
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temp2 = ror(b3.hbyte,3) and 11100000b; /* get 3 bits */
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b3.hbyte = shr(b3.hbyte,3);
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b3.lword = shr(b3.lword,3);
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temp1(1) = temp1(1) or temp2; /* or in 3 bits from hbyte */
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end shr3byte;
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end darithmetic;
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