diff options
Diffstat (limited to 'src/VBox/Devices/BiosCommonCode/__I4M.asm')
| -rw-r--r-- | src/VBox/Devices/BiosCommonCode/__I4M.asm | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/src/VBox/Devices/BiosCommonCode/__I4M.asm b/src/VBox/Devices/BiosCommonCode/__I4M.asm new file mode 100644 index 00000000..99257dde --- /dev/null +++ b/src/VBox/Devices/BiosCommonCode/__I4M.asm @@ -0,0 +1,80 @@ +; $Id: __I4M.asm $ +;; @file +; Compiler support routines. +; + +; +; Copyright (C) 2012-2019 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. +; + + +;******************************************************************************* +;* Exported Symbols * +;******************************************************************************* +public __I4M + +if VBOX_BIOS_CPU lt 80386 +extrn NeedToImplementOn8086__I4M:near +endif + + .8086 + +_TEXT segment public 'CODE' use16 + assume cs:_TEXT + +;; +; 32-bit signed multiplication. +; +; @param dx:ax Factor 1. +; @param cx:bx Factor 2. +; @returns dx:ax Result. +; cx, es may be modified; di is preserved +; +__I4M: + pushf +if VBOX_BIOS_CPU ge 80386 + .386 + push eax + push edx + push ecx + push ebx + + rol eax, 16 + mov ax, dx + ror eax, 16 + xor edx, edx + + shr ecx, 16 + mov cx, bx + + imul ecx ; eax * ecx -> edx:eax + + pop ebx + pop ecx + + pop edx + ror eax, 16 + mov dx, ax + add sp, 2 + pop ax + rol eax, 16 + .8086 +else + call NeedToImplementOn8086__I4M +endif + + popf + ret + + +_TEXT ends + end + |