Eremey Valetov
d8e8375366
GW-BASIC reimplementation in C11, using Microsoft's open-sourced 8088 assembly as the authoritative reference. Tokenizer (CRUNCH/LIST), expression evaluator with operator precedence, all math functions (SIN, COS, TAN, ATN, SQR, LOG, EXP, RND, etc.), string functions (LEFT$, RIGHT$, MID$, CHR$, ASC, VAL, STR$, etc.), PRINT statement with comma/semicolon zones, TAB(), SPC(). Handles integer/single/double types with correct promotion, D exponent for double-precision literals, type suffixes (%, !, #), &H hex/&O octal literals, MBF conversion routines, and GW-BASIC-compatible number formatting. Platform-independent via HAL vtable; POSIX backend included.
51 lines
959 B
C
51 lines
959 B
C
#include "gwbasic.h"
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#include <limits.h>
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int16_t gw_int_add(int16_t a, int16_t b)
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{
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int32_t r = (int32_t)a + (int32_t)b;
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if (r < -32768 || r > 32767)
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gw_error(ERR_OV);
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return (int16_t)r;
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}
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int16_t gw_int_sub(int16_t a, int16_t b)
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{
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int32_t r = (int32_t)a - (int32_t)b;
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if (r < -32768 || r > 32767)
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gw_error(ERR_OV);
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return (int16_t)r;
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}
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int16_t gw_int_mul(int16_t a, int16_t b)
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{
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int32_t r = (int32_t)a * (int32_t)b;
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if (r < -32768 || r > 32767)
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gw_error(ERR_OV);
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return (int16_t)r;
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}
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int16_t gw_int_div(int16_t a, int16_t b)
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{
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if (b == 0) gw_error(ERR_DZ);
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if (a == -32768 && b == -1) gw_error(ERR_OV);
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return a / b;
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}
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int16_t gw_int_mod(int16_t a, int16_t b)
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{
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if (b == 0) gw_error(ERR_DZ);
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return a % b;
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}
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int16_t gw_int_idiv(int16_t a, int16_t b)
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{
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return gw_int_div(a, b);
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}
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int16_t gw_int_neg(int16_t a)
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{
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if (a == -32768) gw_error(ERR_OV);
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return -a;
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}
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