diff options
Diffstat (limited to 'sysdeps/x86_64/fpu/e_scalbl.S')
| -rw-r--r-- | sysdeps/x86_64/fpu/e_scalbl.S | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/sysdeps/x86_64/fpu/e_scalbl.S b/sysdeps/x86_64/fpu/e_scalbl.S new file mode 100644 index 0000000000..6b229705ba --- /dev/null +++ b/sysdeps/x86_64/fpu/e_scalbl.S @@ -0,0 +1,100 @@ +/* + * Written by J.T. Conklin <jtc@netbsd.org>. + * Public domain. + * + * Adapted for `long double' by Ulrich Drepper <drepper@cygnus.com>. + * Adapted for x86-64 by Andreas Jaeger <aj@suse.de> + * + * Correct handling of y==-inf <drepper@gnu> + */ + +#include <machine/asm.h> + +RCSID("$NetBSD: $") + +#ifdef __ELF__ + .section .rodata +#else + .text +#endif + + .align ALIGNARG(4) + ASM_TYPE_DIRECTIVE(zero_nan,@object) +zero_nan: + .double 0.0 +nan: .byte 0, 0, 0, 0, 0, 0, 0xff, 0x7f +minus_zero: + .byte 0, 0, 0, 0, 0, 0, 0, 0x80 + .byte 0, 0, 0, 0, 0, 0, 0xff, 0x7f + ASM_SIZE_DIRECTIVE(zero_nan) + + +#ifdef PIC +#define MO(op) op##(%rip) +#else +#define MO(op) op +#endif + + .text +ENTRY(__ieee754_scalbl) + fldt 24(%rsp) + fxam + fnstsw + fldt 8(%rsp) + andl $0x4700, %eax + cmpl $0x0700, %eax + je 1f + andl $0x4500, %eax + cmpl $0x0100, %eax + je 2f + fxam + fnstsw + andl $0x4500, %eax + cmpl $0x0100, %eax + je 3f + fld %st(1) + frndint + fcomip %st(2), %st + jne 4f + fscale + fstp %st(1) + ret + + /* y is -inf */ +1: fxam + fnstsw + movl 16(%rsp), %edx + shrl $5, %eax + fstp %st + fstp %st + andl $0x8000, %edx + andl $8, %eax + jnz 4f + shrl $11, %edx + addl %edx, %eax +#ifdef PIC + lea zero_nan(%rip),%rdx + fldl (%rdx,%rax,1) +#else + fldl zero_nan(%rax, 1) +#endif + ret + + /* The result is NaN, but we must not raise an exception. + So use a variable. */ +2: fstp %st + fstp %st + fldl MO(nan) + ret + + /* The first parameter is a NaN. Return it. */ +3: fstp %st(1) + ret + + /* Return NaN and raise the invalid exception. */ +4: fstp %st + fstp %st + fldz + fdiv %st + ret +END(__ieee754_scalbl) |