From 36c824864c02f0a3f62c8a1d365d1670835c8c96 Mon Sep 17 00:00:00 2001
From: "Christian A. Weber" <chris@gna.ch>
Date: Tue, 12 May 1992 22:26:12 +0000
Subject: Initial revision

---
 Source/GetColorTab.S | 94 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 94 insertions(+)
 create mode 100644 Source/GetColorTab.S

(limited to 'Source/GetColorTab.S')

diff --git a/Source/GetColorTab.S b/Source/GetColorTab.S
new file mode 100644
index 0000000..e7adcb6
--- /dev/null
+++ b/Source/GetColorTab.S
@@ -0,0 +1,94 @@
+**
+**	$Id: $
+**	$Revision: $
+**
+**	$Filename: GetColorTab.S $
+**	$Author: Christian A. Weber $
+**	$Release: 19.1 $
+**	$Date: 92/05/11 21:11:27 $
+**
+**	iff.library/IFFLib_GetColorTab
+**
+**	COPYRIGHT (C) 1987-1992 BY CHRISTIAN A. WEBER, BRUGGERWEG 2,
+**	CH-8037 ZUERICH, SWITZERLAND.  ALL RIGHTS RESERVED.  NO PART
+**	OF THIS SOFTWARE MAY BE COPIED, REPRODUCED,  OR  TRANSMITTED
+**	IN ANY FORM OR BY ANY MEANS,  WITHOUT THE PRIOR WRITTEN PER-
+**	MISSION OF THE AUTHOR. USE AT YOUR OWN RISK.
+**
+
+
+		IDNT	IFFLib_GetColorTab
+		SECTION	text,CODE
+
+		INCLUDE	"IFFLib.i"
+
+		XREF	FindChunkFunc
+		XDEF	GetColorTabFunc
+
+
+******* iff.library/IFFLib_GetColorTab **************************************
+*
+*    NAME
+*	IFFLib_GetColorTab -- find a CMAP and convert it to a ColorTable
+*
+*    SYNOPSIS
+*	count = IFFLib_GetColorTab( ifffile, colortable )
+*	 D0                         A1       A0
+*
+*    FUNCTION
+*	Searches the CMAP chunk of an IFF file and converts it, if it's
+*	there, to an Amiga color table structure. This colortable can
+*	directly be used as a parameter for the LoadRGB4() function.
+*
+*    INPUTS
+*	ifffile - IFF file pointer, returned by IFFLib_OpenIFF()
+*	colortable - Pointer to a block of memory which must be large
+*	             enough to hold the colortable (2 bytes per color).
+*	             Must be WORD aligned.
+*
+*    RESULT
+*	Number of colors actually found, or zero if the file has no
+*	CMAP chunk
+*
+*    SEE ALSO
+*	IFFLib_FindChunk(), IFFLib_GetBMHD()
+*
+*****************************************************************************
+
+GetColorTabFunc:
+		movem.l	d2-d5/a2,-(SP)
+		movea.l	a0,a2			; Ziel-Adresse
+
+		move.l	#'CMAP',d0
+		bsr	FindChunkFunc
+	;;	tst.l	d0
+		beq.s	99$			; nicht gefunden --->
+		movea.l	d0,a0
+
+		addq.l	#4,a0			; Chunk-Namen überlesen
+		move.l	(a0)+,d4		; Chunk-size
+		divs	#3,d4			; Anzahl Farben
+		ext.l	d4			; für D0
+		move.l	d4,d0			; Resultat: Anzahl Farben
+
+		moveq	#256-$f0,d5		; Color-Maske $f0
+		neg.b	d5			; Toebes-Optimierlung
+		bra.s	1$			; Für dbf
+
+.Loop:		move.b	(a0)+,d1		; rot
+		and.w	d5,d1			; Nur Bits 7-4 benützen
+		move.b	(a0)+,d2		; grün
+		and.w	d5,d2			; Nur Bits 7-4 benützen
+		move.b	(a0)+,d3		; blau
+		and.w	d5,d3			; Nur Bits 7-4 benützen
+		lsl.w	#4,d1			; rot  << 4
+		lsr.w	#4,d3			; blau >> 4
+		or.w	d2,d1
+		or.w	d3,d1
+		move.w	d1,(a2)+		; in Farbtabelle eintragen
+1$:		dbf	d4,.Loop
+99$:
+		movem.l	(SP)+,d2-d5/a2
+		rts
+
+		END
-- 
cgit v1.2.3