The OpenD Programming Language

muls

Multiply two signed integers, checking for overflow.

The overflow is sticky, meaning a sequence of operations can be done and overflow need only be checked at the end.

  1. int muls(int x, int y, bool overflow)
    nothrow @safe @nogc pure pragma(inline, true)
    int
    muls
    ()
    (
    int x
    ,
    int y
    ,
    ref bool overflow
    )
  2. long muls(long x, long y, bool overflow)
  3. cent muls(cent x, cent y, bool overflow)

Parameters

x int

left operand

y int

right operand

overflow bool

set if an overflow occurs, is not affected otherwise

Return Value

Type: int

the product

Examples

bool overflow;
assert(muls(2, 3, overflow) == 6);
assert(!overflow);

assert(muls(-200, 300, overflow) == -60_000);
assert(!overflow);

assert(muls(1, int.max, overflow) == int.max);
assert(!overflow);

assert(muls(int.min, 1, overflow) == int.min);
assert(!overflow);

assert(muls(int.max, 2, overflow) == (int.max * 2));
assert(overflow);

overflow = false;
assert(muls(int.min, -1, overflow) == int.min);
assert(overflow);

assert(muls(0, 0, overflow) == 0);
assert(overflow);                   // sticky
bool overflow;
assert(muls(2L, 3L, overflow) == 6);
assert(!overflow);

assert(muls(-200L, 300L, overflow) == -60_000);
assert(!overflow);

assert(muls(1, long.max, overflow) == long.max);
assert(!overflow);

assert(muls(long.min, 1L, overflow) == long.min);
assert(!overflow);

assert(muls(long.max, 2L, overflow) == (long.max * 2));
assert(overflow);
overflow = false;

assert(muls(-1L, long.min, overflow) == long.min);
assert(overflow);

overflow = false;
assert(muls(long.min, -1L, overflow) == long.min);
assert(overflow);

assert(muls(0L, 0L, overflow) == 0);
assert(overflow);                   // sticky

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