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 <asm.inc>
  12 #include <ksamd64.inc>
  13
  14 /* FUNCTIONS ****************************************************************/
  15
  16 .code64
  17
  18 PUBLIC floorf
  19 floorf:
  20     sub rsp, 16
  21
  22     /* Put parameter on the stack */
  23     movss [rsp], xmm0
  24     fld   dword ptr [rsp]
  25
  26     /* Change fpu control word to round down */
  27     fstcw [rsp]
  28     mov   eax, [rsp]
  29     or    eax, 0x00400
  30     and   eax, 0x0f7ff
  31     mov   [rsp + 8], eax
  32     fldcw [rsp + 8]
  33
  34     /* Round to integer */
  35     frndint
  36
  37     /* Restore fpu control word */
  38     fldcw [rsp]
  39
  40     fstp  dword ptr [rsp]
  41     movss xmm0, [rsp]
  42     add rsp, 16
  43     ret
  44
  45 END