23 lines
929 B
C
23 lines
929 B
C
#include <stdint.h>
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//#include "int_lib.h"
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// Returns: a / b
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#define CHAR_BIT 8
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int32_t __divsi3(int32_t a, int32_t b) {
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const int bits_in_word_m1 = (int)(sizeof(int32_t) * CHAR_BIT) - 1;
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int32_t s_a = a >> bits_in_word_m1; // s_a = a < 0 ? -1 : 0
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int32_t s_b = b >> bits_in_word_m1; // s_b = b < 0 ? -1 : 0
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//xprintf("divsi3(1):a=%d, b=%d, s_a=%d, s_b=%s\n", a, b, s_a, s_b);
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a = (a ^ s_a) - s_a; // negate if s_a == -1
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b = (b ^ s_b) - s_b; // negate if s_b == -1
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s_a ^= s_b; // sign of quotient
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//xprintf("divsi3(2):a=%d, b=%d, s_a=%d, s_b=%s\n", a, b, s_a, s_b);
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// On CPUs without unsigned hardware division support,
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// this calls __udivsi3 (notice the cast to su_int).
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// On CPUs with unsigned hardware division support,
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// this uses the unsigned division instruction.
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//
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return ((uint32_t)a / (uint32_t)b ^ s_a) - s_a; // negate if s_a == -1
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}
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