summaryrefslogtreecommitdiffstats
path: root/src/VBox/Runtime/common/math/trunc.asm
diff options
context:
space:
mode:
Diffstat (limited to 'src/VBox/Runtime/common/math/trunc.asm')
-rw-r--r--src/VBox/Runtime/common/math/trunc.asm68
1 files changed, 68 insertions, 0 deletions
diff --git a/src/VBox/Runtime/common/math/trunc.asm b/src/VBox/Runtime/common/math/trunc.asm
new file mode 100644
index 00000000..cb1b566c
--- /dev/null
+++ b/src/VBox/Runtime/common/math/trunc.asm
@@ -0,0 +1,68 @@
+; $Id: trunc.asm $
+;; @file
+; IPRT - No-CRT trunc - AMD64 & X86.
+;
+
+;
+; Copyright (C) 2006-2019 Oracle Corporation
+;
+; This file is part of VirtualBox Open Source Edition (OSE), as
+; available from http://www.virtualbox.org. This file is free software;
+; you can redistribute it and/or modify it under the terms of the GNU
+; General Public License (GPL) as published by the Free Software
+; Foundation, in version 2 as it comes in the "COPYING" file of the
+; VirtualBox OSE distribution. VirtualBox OSE is distributed in the
+; hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
+;
+; The contents of this file may alternatively be used under the terms
+; of the Common Development and Distribution License Version 1.0
+; (CDDL) only, as it comes in the "COPYING.CDDL" file of the
+; VirtualBox OSE distribution, in which case the provisions of the
+; CDDL are applicable instead of those of the GPL.
+;
+; You may elect to license modified versions of this file under the
+; terms and conditions of either the GPL or the CDDL or both.
+;
+
+
+%include "iprt/asmdefs.mac"
+
+BEGINCODE
+
+;;
+; Round to truncated integer value.
+; @returns 32-bit: st(0) 64-bit: xmm0
+; @param rd 32-bit: [ebp + 8] 64-bit: xmm0
+BEGINPROC RT_NOCRT(trunc)
+ push xBP
+ mov xBP, xSP
+ sub xSP, 10h
+
+%ifdef RT_ARCH_AMD64
+ movsd [xSP], xmm0
+ fld qword [xSP]
+%else
+ fld qword [xBP + xCB*2]
+%endif
+
+ ; Make it truncate up by modifying the fpu control word.
+ fstcw [xBP - 10h]
+ mov eax, [xBP - 10h]
+ or eax, 00c00h
+ mov [xBP - 08h], eax
+ fldcw [xBP - 08h]
+
+ ; Round ST(0) to integer.
+ frndint
+
+ ; Restore the fpu control word.
+ fldcw [xBP - 10h]
+
+%ifdef RT_ARCH_AMD64
+ fstp qword [xSP]
+ movsd xmm0, [xSP]
+%endif
+ leave
+ ret
+ENDPROC RT_NOCRT(trunc)
+