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Implement floored / and divisor-sign % operators (#745)

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Fixes #703
This commit is contained in:
Rangi
2021-02-21 13:14:44 -08:00
committed by GitHub
parent a6d844a9a5
commit 5fd636ac4b
8 changed files with 85 additions and 9 deletions
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22
src/asm/rpn.c
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@@ -283,6 +283,22 @@ static int32_t shift(int32_t shiftee, int32_t amount)
}
}
static int32_t divide(int32_t dividend, int32_t divisor)
{
// Adjust division to floor toward negative infinity,
// not truncate toward zero
return dividend / divisor - ((dividend % divisor < 0) != (divisor < 0));
}
static int32_t modulo(int32_t dividend, int32_t divisor)
{
int32_t remainder = dividend % divisor;
// Adjust modulo to have the sign of the divisor,
// not the sign of the dividend
return remainder + divisor * ((remainder < 0) != (divisor < 0));
}
static int32_t exponent(int32_t base, uint32_t power)
{
int32_t result = 1;
@@ -410,17 +426,17 @@ void rpn_BinaryOp(enum RPNCommand op, struct Expression *expr,
PRId32 "\n", INT32_MIN, INT32_MIN);
expr->nVal = INT32_MIN;
} else {
expr->nVal = src1->nVal / src2->nVal;
expr->nVal = divide(src1->nVal, src2->nVal);
}
break;
case RPN_MOD:
if (src2->nVal == 0)
fatalerror("Division by zero\n");
fatalerror("Modulo by zero\n");
if (src1->nVal == INT32_MIN && src2->nVal == -1)
expr->nVal = 0;
else
expr->nVal = src1->nVal % src2->nVal;
expr->nVal = modulo(src1->nVal, src2->nVal);
break;
case RPN_EXP:
if (src2->nVal < 0)