newlib-cygwin/winsup/mingw/mingwex/math/ilogb.S

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/*
* Written by J.T. Conklin <jtc@netbsd.org>.
* Public domain.
*/
.file "ilogb.S"
.text
.align 4
.globl _ilogb
.def _ilogb; .scl 2; .type 32; .endef
_ilogb:
fldl 4(%esp)
/* I added the following ugly construct because ilogb(+-Inf) is
required to return INT_MAX in ISO C99.
-- jakub@redhat.com. */
fxam /* Is NaN or +-Inf? */
fstsw %ax
movb $0x45, %dh
andb %ah, %dh
cmpb $0x05, %dh
je 1f /* Is +-Inf, jump. */
fxtract
pushl %eax
fstp %st
fistpl (%esp)
fwait
popl %eax
ret
1: fstp %st
movl $0x7fffffff, %eax
ret