In MIPS architecture, is the result of 0x80000000/-1 undefined?
The operands of DIV instruction 32bit signed int.
0x7fff_ffff = 2,147,483,647 (INT_MAX)
0x8000_0000 = -2,147,483,648 (INT_MIN)
limits.h defines them as;
> /* Minimum and maximum values a `signed int' can hold. */
> # define INT_MIN (- INT_MAX - 1)
> # define INT_MAX 2147483647
0x8000_0000 / 0xffff_ffff = -2,147,483,648 / -1 = 2,147,483,648 > INT_MAX
But the description of the DIV instruction of MIPS RISC Architecture
(Kane and Heinrich) says;
No overflow exception occurs under any circumstances, and the
result of this operation is undefined when the divisor is zero.
According to 'See MIPS Run', P.186, MIPS assembler expands a div
instruction to an instruction sequence in which these condition are
checked. Do all MIPS assemblers do this?
Any information is welcome.
Thank you.
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Hiroo Hayashi System LSI Architecture Dept.
Computer on Silicon Development Center
TOSHIBA Corporation
