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/*
* Written by J.T. Conklin <jtc@netbsd.org>.
* Public domain.
* Adapted for float type by Ulrich Drepper <drepper@cygnus.com>.
*/
#include <machine/asm.h>
.section .rodata.cst4,"aM",@progbits,4
.p2align 2
.type flt_min,@object
flt_min: .byte 0, 0, 0x80, 0
ASM_SIZE_DIRECTIVE(flt_min)
#ifdef PIC
# define MO(op) op##@GOTOFF(%ecx)
#else
# define MO(op) op
#endif
.text
/* e^x = 2^(x * log2(e)) */
ENTRY(__ieee754_expf)
#ifdef PIC
LOAD_PIC_REG (cx)
#endif
flds 4(%esp)
/* I added the following ugly construct because exp(+-Inf) resulted
in NaN. The ugliness results from the bright minds at Intel.
For the i686 the code can be written better.
-- drepper@cygnus.com. */
fxam /* Is NaN or +-Inf? */
fstsw %ax
movb $0x45, %dh
andb %ah, %dh
cmpb $0x05, %dh
je 1f /* Is +-Inf, jump. */
fldl2e
fmulp /* x * log2(e) */
fld %st
frndint /* int(x * log2(e)) */
fsubr %st,%st(1) /* fract(x * log2(e)) */
fxch
f2xm1 /* 2^(fract(x * log2(e))) - 1 */
fld1
faddp /* 2^(fract(x * log2(e))) */
fscale /* e^x */
fstp %st(1)
flds MO(flt_min)
fld %st(1)
fucompp
fnstsw
sahf
jnc 3f
subl $4, %esp
cfi_adjust_cfa_offset (4)
fld %st(0)
fmul %st(0)
fstps (%esp)
fstps (%esp)
flds (%esp)
addl $4, %esp
cfi_adjust_cfa_offset (-4)
3: ret
1: testl $0x200, %eax /* Test sign. */
jz 2f /* If positive, jump. */
fstp %st
fldz /* Set result to 0. */
2: ret
END (__ieee754_expf)
ENTRY(__expf_finite)
#ifdef PIC
LOAD_PIC_REG (cx)
#endif
fldl2e
fmuls 4(%esp) /* x * log2(e) */
fld %st
frndint /* int(x * log2(e)) */
fsubr %st,%st(1) /* fract(x * log2(e)) */
fxch
f2xm1 /* 2^(fract(x * log2(e))) - 1 */
fld1
faddp /* 2^(fract(x * log2(e))) */
fscale /* e^x */
fstp %st(1)
flds MO(flt_min)
fld %st(1)
fucompp
fnstsw
sahf
jnc 4f
subl $4, %esp
cfi_adjust_cfa_offset (4)
fld %st(0)
fmul %st(0)
fstps (%esp)
fstps (%esp)
flds (%esp)
addl $4, %esp
cfi_adjust_cfa_offset (-4)
4: ret
END(__expf_finite)
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