5980be9b3c
This work is based in part on code from NetBSD libm, libc and kernel. The library is partly public domain and partly BSD-style licensed.
56 lines
1,022 B
ArmAsm
56 lines
1,022 B
ArmAsm
/*
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* Written by J.T. Conklin <jtc@NetBSD.org>.
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* Public domain.
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*/
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#include <machine/asm.h>
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#include "abi.h"
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RCSID("$NetBSD: e_expf.S,v 1.6 2008/06/24 17:27:56 drochner Exp $")
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/* e^x = 2^(x * log2(e)) */
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ENTRY(__ieee754_expf)
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XMM_ONE_ARG_FLOAT_PROLOGUE
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/*
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* catch +/-Inf and NaN arguments
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*/
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movl ARG_FLOAT_ONE,%eax
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andl $0x7fffffff,%eax
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cmpl $0x7f800000,%eax
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jae x_Inf_or_NaN
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flds ARG_FLOAT_ONE
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fldl2e
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fmulp /* x * log2(e) */
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fld %st(0)
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frndint /* int(x * log2(e)) */
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fsubr %st(0),%st(1) /* fract(x * log2(e)) */
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fxch
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f2xm1 /* 2^(fract(x * log2(e))) - 1 */
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fld1
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faddp /* 2^(fract(x * log2(e))) */
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fscale /* e^x */
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fstp %st(1)
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XMM_FLOAT_EPILOGUE
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ret
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x_Inf_or_NaN:
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/*
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* Return 0 if x is -Inf. Otherwise just return x, although the
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* C version would return (x + x) (Real Indefinite) if x is a NaN.
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*/
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movl ARG_FLOAT_ONE,%eax
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cmpl $0xff800000,%eax
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jne x_not_minus_Inf
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fldz
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XMM_FLOAT_EPILOGUE
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ret
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x_not_minus_Inf:
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flds ARG_FLOAT_ONE
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XMM_FLOAT_EPILOGUE
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ret
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