/* * Written by J.T. Conklin . * Public domain. * * Adapted for `long double' by Ulrich Drepper . * Adapted for x86-64 by Andreas Jaeger * * Correct handling of y==-inf */ #include 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)