Difference between revisions of "Programming:Fast plot"

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(Changed &X into % - (old code which I used with another compiler))
m (Sorted routines by mode)
Line 1: Line 1:
== Fast plotting routine for MODE 1 ==
+
== Fast plotting routine for MODE 0 ==
  
This routine is approx. 6 times faster than the OS routine GRA PLOT, because it is dpendent to MODE 1 and doesn't perform range checks. It can draw 10500 pixels per second.
+
Converted from the Mode 1 routine by [[User:Executioner|The Executioner]]
  
'''Input:''' DE = ''X (0..319)'', HL = ''Y (0..199)''
+
'''Input:''' DE = ''X (0..159)'', HL = ''Y (0..199)''
  
 
<pre>
 
<pre>
Line 22: Line 22:
 
ADD HL, HL ;of the raster line
 
ADD HL, HL ;of the raster line
 
 
LD A, E ;Lowbyte X to A
+
SRL D ;calculate X\2, because
SRL D ;calculate X\4, because
+
RR E ;2 pixel per byte, Carry is X MOD 2
RR E ;4 pixel per byte
+
SRL E
+
ADD HL, DE ;+ HL = Screenaddress
+
 
 
LD C, %10001000 ;Bitmask for MODE 1
+
LD C, %10101010         ;Bitmask for MODE 1
AND %00000011 ;A = X MOD 4
+
JR NC, NSHIFT ;-> = 0, no shift
JR Z, NSHIFT ;-> = 0, no shift
+
SHIFT LD C, %01010101         ;other bitmask for right pixel
SHIFT SRL C ;move bitmask to pixel
+
DEC A ;loop counter
+
JR NZ,SHIFT ;-position
+
 
 
NSHIFT LD A, (CMASK) ;get color mask
+
NSHIFT ADD HL, DE ;+ HL = Screenaddress
 +
        LD A, (CMASK) ;get color mask
 
XOR (HL) ;XOR screenbyte
 
XOR (HL) ;XOR screenbyte
 
AND C ;AND bitmask
 
AND C ;AND bitmask
Line 44: Line 39:
  
  
== Fast plotting routine for MODE 0 ==
+
== Fast plotting routine for MODE 1 ==
  
Converted from the above by [[User:Executioner|The Executioner]]
+
This routine is approx. 6 times faster than the OS routine GRA PLOT, because it is dpendent to MODE 1 and doesn't perform range checks. It can draw 10500 pixels per second.
  
'''Input:''' DE = ''X (0..159)'', HL = ''Y (0..199)''
+
'''Input:''' DE = ''X (0..319)'', HL = ''Y (0..199)''
  
 
<pre>
 
<pre>
Line 67: Line 62:
 
ADD HL, HL ;of the raster line
 
ADD HL, HL ;of the raster line
 
 
SRL D ;calculate X\2, because
+
LD A, E ;Lowbyte X to A
RR E ;2 pixel per byte, Carry is X MOD 2
+
SRL D ;calculate X\4, because
 +
RR E ;4 pixel per byte
 +
SRL E
 +
ADD HL, DE ;+ HL = Screenaddress
 
 
LD C, %10101010         ;Bitmask for MODE 1
+
LD C, %10001000 ;Bitmask for MODE 1
JR NC, NSHIFT ;-> = 0, no shift
+
AND %00000011 ;A = X MOD 4
SHIFT LD C, %01010101         ;other bitmask for right pixel
+
JR Z, NSHIFT ;-> = 0, no shift
 +
SHIFT SRL C ;move bitmask to pixel
 +
DEC A ;loop counter
 +
JR NZ,SHIFT ;-position
 
 
NSHIFT ADD HL, DE ;+ HL = Screenaddress
+
NSHIFT LD A, (CMASK) ;get color mask
        LD A, (CMASK) ;get color mask
+
 
XOR (HL) ;XOR screenbyte
 
XOR (HL) ;XOR screenbyte
 
AND C ;AND bitmask
 
AND C ;AND bitmask

Revision as of 04:16, 24 August 2006

Fast plotting routine for MODE 0

Converted from the Mode 1 routine by The Executioner

Input: DE = X (0..159), HL = Y (0..199)

CMASK	EQU &B338		;Adress for colormask
				;664/6128: &B6A3
						
FPLOT	LD A, L			;A = Lowbyte Y
	AND %00000111		;isolate Bit 0..2
	LD H, A			;= y MOD 8 to H
	XOR L			;A = Bit 3..7 of Y
	LD L, A			;= (Y\8)*8 to L
	LD C, A			;store in C
	LD B, &60		;B = &C0\2 = Highbyte Screenstart\2
		
	ADD HL, HL		;HL * 2
	ADD HL, HL		;HL * 4
	ADD HL, BC		;+ BC = Startaddress
	ADD HL, HL		;of the raster line
		
	SRL D			;calculate X\2, because
	RR E			;2 pixel per byte, Carry is X MOD 2
		
	LD C, %10101010	        ;Bitmask for MODE 1
	JR NC, NSHIFT		;-> = 0, no shift
SHIFT 	LD C, %01010101	        ;other bitmask for right pixel
		
NSHIFT	ADD HL, DE		;+ HL = Screenaddress
        LD A, (CMASK)		;get color mask
	XOR (HL)		;XOR screenbyte
	AND C			;AND bitmask
	XOR (HL)		;XOR screenbyte
	LD (HL), A		;new screenbyte
	RET			;done


Fast plotting routine for MODE 1

This routine is approx. 6 times faster than the OS routine GRA PLOT, because it is dpendent to MODE 1 and doesn't perform range checks. It can draw 10500 pixels per second.

Input: DE = X (0..319), HL = Y (0..199)

CMASK	EQU &B338		;Adress for colormask
				;664/6128: &B6A3
						
FPLOT	LD A, L			;A = Lowbyte Y
	AND %00000111		;isolate Bit 0..2
	LD H, A			;= y MOD 8 to H
	XOR L			;A = Bit 3..7 of Y
	LD L, A			;= (Y\8)*8 to L
	LD C, A			;store in C
	LD B, &60		;B = &C0\2 = Highbyte Screenstart\2
		
	ADD HL, HL		;HL * 2
	ADD HL, HL		;HL * 4
	ADD HL, BC		;+ BC = Startaddress
	ADD HL, HL		;of the raster line
		
	LD A, E			;Lowbyte X to A
	SRL D			;calculate X\4, because
	RR E			;4 pixel per byte
	SRL E
	ADD HL, DE		;+ HL = Screenaddress
		
	LD C, %10001000		;Bitmask for MODE 1
	AND %00000011		;A = X MOD 4
	JR Z, NSHIFT		;-> = 0, no shift
SHIFT 	SRL C			;move bitmask to pixel
	DEC A			;loop counter
	JR NZ,SHIFT		;-position
		
NSHIFT	LD A, (CMASK)		;get color mask
	XOR (HL)		;XOR screenbyte
	AND C			;AND bitmask
	XOR (HL)		;XOR screenbyte
	LD (HL), A		;new screenbyte
	RET			;done