if vs ?: - (nf)
Mark Brukhartz
mark at laidbak.UUCP
Tue Feb 21 09:42:58 AEST 1984
Some machine-dependent code uses "discarded values" for parameters
to asm() (assembly language) escapes. For example:
a + b; /* Assume result goes to r0 */
asm(" (something using r0) "); /* Do something funny with r0 */
The "a + b" could just as easily be "a < b ? a++ : b++". Such code
assumes that the compiler and optimizer will not ignore the "unneeded"
statement or value.
Quite a bit of recent Berkeley code uses asm() escapes to generate fast
VAX code. I don't like this any more than you do, but it's something to
keep in mind when considering a change to the compiler.
Mark Brukhartz
{allegra,ihnp4,ittral,trsvax}!laidbak!mark
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