view src/video/riscos/SDL_riscosASM.S @ 2661:d38309be5178 gsoc2008_audio_resampling

The windowed sinc filter generation code seems to be working fine. The FIR filtering code is also now working reasonably well. Occasionally the FIR filter will pop, but setting the normalization factor lower seems to help this. I suspect the problem is in the fixed point multiply/add. I also have a hunch the zero stuffing/sample discarding code is not correct, and I'll look at that soon to get it sorted out.
author Aaron Wishnick <schnarf@gmail.com>
date Wed, 02 Jul 2008 08:04:50 +0000
parents 1e8582152d44
children 99210400e8b9
line wrap: on
line source

;
;    SDL - Simple DirectMedia Layer
;    Copyright (C) 1997-2004 Sam Lantinga
;
;    This library is free software; you can redistribute it and/or
;    modify it under the terms of the GNU Library General Public
;    License as published by the Free Software Foundation; either
;    version 2 of the License, or (at your option) any later version.
;
;    This library 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
;    Library General Public License for more details.
;
;    You should have received a copy of the GNU Library General Public
;    License along with this library; if not, write to the Free
;    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
;
;    Sam Lantinga
;    slouken@libsdl.org
;
; Assembler routines for RISC OS display
;

	AREA |C$$CODE|

	EXPORT |RISCOS_Put32|

; Display 32bpp to 32bpp, 1:1
;
; Code provided by Adrain Lees
;
; entry a1 -> destination
;       a2 =  dest width in pixels
;       a3 =  dest line length in bytes
;       a4 =  dest height in scanlines
;       arg5 -> source
;       arg6 =  byte offset from end of source line to start of next

Arg5    *       10*4
Arg6    *       Arg5+4

RISCOS_Put32    ROUT
                STMFD   sp!,{a2,v1-v6,sl,fp,lr}
                LDR     ip,[sp,#Arg5]
                MOV     lr,a1
                B       ucp64lp

00              ;tail strip of 1-15 pixels

                LDR     v1,[ip],#4
01              SUBS    a2,a2,#1
                STR     v1,[lr],#4
                LDRHI   v1,[ip],#4
                BHI     %01
                B       %02

ucp64end        ADDS    a2,a2,#16
                BNE     %00

02              SUBS    a4,a4,#1                ;height--
                LDRHI   v1,[sp,#Arg6]
                LDRHI   a2,[sp]                 ;reload width
                BLS     %03

                ;move to start of next scanline

                ADD     lr,a1,a3
                ADD     a1,a1,a3
                ADD     ip,ip,v1

ucp64lp         SUBS    a2,a2,#16
                BLO     ucp64end

                PLD     [ip,#64]

                LDR     v1,[ip],#4
                LDR     v2,[ip],#4
                LDR     v3,[ip],#4
                LDR     v4,[ip],#4
                LDR     v5,[ip],#4
                LDR     v6,[ip],#4
                LDR     sl,[ip],#4
                LDR     fp,[ip],#4
                STR     v1,[lr],#4
                STR     v2,[lr],#4
                STR     v3,[lr],#4
                STR     v4,[lr],#4
                STR     v5,[lr],#4
                STR     v6,[lr],#4
                STR     sl,[lr],#4
                STR     fp,[lr],#4

                PLD     [ip,#64]

                LDR     v1,[ip],#4
                LDR     v2,[ip],#4
                LDR     v3,[ip],#4
                LDR     v4,[ip],#4
                LDR     v5,[ip],#4
                LDR     v6,[ip],#4
                LDR     sl,[ip],#4
                LDR     fp,[ip],#4
                STR     v1,[lr],#4
                STR     v2,[lr],#4
                STR     v3,[lr],#4
                STR     v4,[lr],#4
                STR     v5,[lr],#4
                STR     v6,[lr],#4
                STR     sl,[lr],#4
                STR     fp,[lr],#4

                B       ucp64lp

03              LDMFD   sp!,{a2,v1-v6,sl,fp,pc}