reactos/lib/sdk/crt/math/amd64/floorf.S

   1 /*
   2  * COPYRIGHT:         See COPYING in the top level directory
   3  * PROJECT:           ReactOS system libraries
   4  * PURPOSE:           Implementation of tan
   5  * FILE:              lib/sdk/crt/math/amd64/floorf.S
   6  * PROGRAMMER:        Timo Kreuzer (timo.kreuzer@reactos.org)
   7  */
   8
   9 /* INCLUDES ******************************************************************/
  10
  11 #include <ndk/amd64/asm.h>
  12 #include <ndk/amd64/asmmacro.S>
  13
  14 .intel_syntax noprefix
  15
  16
  17 .proc floorf
  18     /* Put parameter on the stack */
  19     movss [rsp - 0x10], xmm0
  20     fld   dword ptr [rsp]
  21
  22     /* Change fpu control word to round down */
  23     fstcw [rsp - 0x10]
  24     mov   eax, [rsp - 0x10]
  25     or    eax, 0x00400
  26     and   eax, 0x0f7ff
  27     mov   [rsp - 0x08], eax
  28     fldcw [rsp - 0x08]
  29
  30     /* Round to integer */
  31     frndint
  32
  33     /* Restore fpu control word */
  34     fldcw [rsp - 0x10]
  35
  36     fstp  dword ptr [rsp - 0x10]
  37     movss xmm0, [rsp - 0x10]
  38     ret
  39
  40 .endproc