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56 lines
1.2 KiB
ArmAsm
56 lines
1.2 KiB
ArmAsm
/*
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* COPYRIGHT: See COPYING in the top level directory
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* PROJECT: ReactOS system libraries
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* PURPOSE: Implementation of ceil
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* FILE: lib/sdk/crt/math/amd64/ceil.S
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* PROGRAMMER: Timo Kreuzer (timo.kreuzer@reactos.org)
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*/
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/* INCLUDES ******************************************************************/
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#include <asm.inc>
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#include <ksamd64.inc>
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/* CODE **********************************************************************/
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.code64
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/* ceil(x) = - floor(-x)
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*/
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PUBLIC ceil
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.PROC ceil
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sub rsp, 16
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.ENDPROLOG
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/* Duplicate the bits into rax */
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movd rax, xmm0
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/* Invert the sign bit */
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rol rax, 1
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xor al, 1
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ror rax, 1
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/* Copy back to xmm0 */
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movd xmm0, rax
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/* Truncate xmm0 to integer (double precision) */
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cvttsd2si rcx, xmm0
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/* Shift all bits to the right, keeping the sign bit */
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shr rax, 63
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/* Substract the sign bit from the truncated value, so that
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we get the correct result for negative values. */
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sub rcx, rax
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/* Now compensate for the previous negation */
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neg rcx
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/* Convert the result back to xmm0 (double precision) */
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cvtsi2sd xmm0, rcx
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add rsp, 16
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ret
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.ENDP
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END
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