CnC_Red_Alert/WIN32LIB/SRCDEBUG/DS_RSS.ASM

110 lines
5.2 KiB
NASM
Raw Normal View History

;
; Command & Conquer Red Alert(tm)
; Copyright 2025 Electronic Arts Inc.
;
; This program is free software: you can redistribute it and/or modify
; it under the terms of the GNU General Public License as published by
; the Free Software Foundation, either version 3 of the License, or
; (at your option) any later version.
;
; This program is distributed in the hope that it will be useful,
; but WITHOUT ANY WARRANTY; without even the implied warranty of
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
; GNU General Public License for more details.
;
; You should have received a copy of the GNU General Public License
; along with this program. If not, see <http://www.gnu.org/licenses/>.
;
;***************************************************************************
;** C O N F I D E N T I A L --- W E S T W O O D A S S O C I A T E S **
;***************************************************************************
;* *
;* Project Name : Draw Shape Routines for library. *
;* *
;* File Name : DS_RSS.ASM *
;* *
;* Programmer : Scott K. Bowen *
;* *
;* Start Date : August 24, 1993 *
;* *
;* Last Update : June 1, 1994 [BR] *
;* *
;*-------------------------------------------------------------------------*
;* Functions: *
;* Right_Scale_Skip -- Skips past a scaled row of pixels on right side *
;* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - *
;********************* Model & Processor Directives ************************
IDEAL
P386
MODEL USE32 FLAT
;******************************** Includes *********************************
INCLUDE "shape.inc"
;********************************* Code ************************************
CODESEG
;***************************************************************************
;* Right_Scale_Skip -- Skips past a scaled row of pixels on the right side *
;* *
;* INPUT: *
;* ECX = number of uncompressed bytes to skip *
;* ESI = shape buffer data address *
;* *
;* OUTPUT: *
;* ESI - updated to the current location in the shape data *
;* *
;* WARNINGS: This routine may overrun the number of requested bytes *
;* if it encounters a run of 0's; however, it's assumed that *
;* the shape data will never contain a run that goes past the *
;* right-hand edge of the shape. *
;* *
;* HISTORY: *
;* 04/20/1992 PWG : Created. *
;* 08/19/1993 SKB : Split drawshp.asm into several modules. *
;* 06/01/1994 BR : Converted to 32-bit *
;*=========================================================================*
PROC Right_Scale_Skip NOLANGUAGE NEAR
;--------------------------------------------------------------------
; Put shape data address in EDI so we can do a scasb on it
;--------------------------------------------------------------------
xchg esi,edi ; xchange ESI and EDI
jecxz ??out ; exit if ECX is 0 (no bytes to skip)
;--------------------------------------------------------------------
; Search through the string and count down the info we have handled.
; If we find a run (0 followed by a count byte), then handle it.
;--------------------------------------------------------------------
??cliptop:
mov eax,0 ; set al to 0 (we're scanning for 0)
repne scasb ; scan through source data
jz ??on_run ; if it is a run then deal with it
jecxz ??out ; if we're done then get outta here
;--------------------------------------------------------------------
; If we have a run then get the next byte which is the length.
;--------------------------------------------------------------------
??on_run:
mov al,[BYTE PTR edi] ; get the count of zeros to run
inc edi ; advance past the count
inc ecx ; the 0 found doesn't count
sub ecx,eax ; subtract the count from remaining
jg ??cliptop ; if more bytes left, scan again
;--------------------------------------------------------------------
; Put shape address back into ESI, adjust EDI
;--------------------------------------------------------------------
??out:
xchg esi,edi ; xchange ESI and EDI
ret ; return back to the real function
ENDP Right_Scale_Skip
END
;*************************** End of ds_rss.asm *****************************