SRB2/src/tmap_vc.nas
spherallic 14295ac7de 2022
2022-03-03 20:24:46 +01:00

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;; SONIC ROBO BLAST 2
;;-----------------------------------------------------------------------------
;; Copyright (C) 1998-2000 by DooM Legacy Team.
;; Copyright (C) 1999-2022 by Sonic Team Junior.
;;
;; This program is free software distributed under the
;; terms of the GNU General Public License, version 2.
;; See the 'LICENSE' file for more details.
;;-----------------------------------------------------------------------------
;; FILE:
;; tmap_vc.nas
;; DESCRIPTION:
;; Assembler optimised math code for Visual C++.
[BITS 32]
%macro cglobal 1
%define %1 _%1
[global %1]
%endmacro
[SECTION .text write]
;----------------------------------------------------------------------------
;fixed_t FixedMul (fixed_t a, fixed_t b)
;----------------------------------------------------------------------------
cglobal FixedMul
; align 16
FixedMul:
mov eax,[esp+4]
imul dword [esp+8]
shrd eax,edx,16
ret
;----------------------------------------------------------------------------
;fixed_t FixedDiv2 (fixed_t a, fixed_t b);
;----------------------------------------------------------------------------
cglobal FixedDiv2
; align 16
FixedDiv2:
mov eax,[esp+4]
mov edx,eax ;; these two instructions allow the next
sar edx,31 ;; two to pair, on the Pentium processor.
shld edx,eax,16
sal eax,16
idiv dword [esp+8]
ret