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corelib: restore new PUTPIXEL implementation

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slederer 2026-02-01 22:46:18 +01:00
parent f90d52926f
commit 885e50c1c0
1 changed files with 34 additions and 156 deletions
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190
lib/corelib.s
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@ -706,108 +706,32 @@ CMPWORDS_XT2:
.EQU FB_PS $90C
.EQU FB_PD $910
.EQU FB_CTL $914
; set a pixel in fb memory
; parameters: x,y - coordinates
PUTPIXEL_1BPP:
; calculate vmem address:
OVER ; duplicate x
; divide x by 32
SHR
SHR
SHR
SHR
SHR
SWAP
; multiply y by words per line
SHL 2
SHL 2
SHL
.EQU FB_SHIFTER $918
.EQU FB_SHIFTCOUNT $91C
.EQU FB_SHIFTERM $920
.EQU FB_SHIFTERSP $924
.EQU FB_MASKGEN $928
ADD ; add results together for vmem addr
; draw a single pixel
; args: x, y, color
DUP
LOADCP FB_WA
SWAP
STOREI ; store to framebuffer write addr register
DROP
LOADCP FB_RA ; and to framebuffer read addr register
SWAP
STOREI
DROP
; x is now at top of stack
; get bit value from x modulo 32
LOADC 31
AND
SHL 2 ; (x & 31) * 4 = offset into table
LOADCP INT_TO_PIX_TABLE
ADD
LOADI
LOADCP FB_IO
; read old vmem value
LOADCP FB_IO
LOADI
; or in new bit
OR
; write new value
STOREI
DROP
RET
INT_TO_PIX_TABLE:
.WORD %10000000_00000000_00000000_00000000
.WORD %01000000_00000000_00000000_00000000
.WORD %00100000_00000000_00000000_00000000
.WORD %00010000_00000000_00000000_00000000
.WORD %00001000_00000000_00000000_00000000
.WORD %00000100_00000000_00000000_00000000
.WORD %00000010_00000000_00000000_00000000
.WORD %00000001_00000000_00000000_00000000
.WORD %00000000_10000000_00000000_00000000
.WORD %00000000_01000000_00000000_00000000
.WORD %00000000_00100000_00000000_00000000
.WORD %00000000_00010000_00000000_00000000
.WORD %00000000_00001000_00000000_00000000
.WORD %00000000_00000100_00000000_00000000
.WORD %00000000_00000010_00000000_00000000
.WORD %00000000_00000001_00000000_00000000
.WORD %00000000_00000000_10000000_00000000
.WORD %00000000_00000000_01000000_00000000
.WORD %00000000_00000000_00100000_00000000
.WORD %00000000_00000000_00010000_00000000
.WORD %00000000_00000000_00001000_00000000
.WORD %00000000_00000000_00000100_00000000
.WORD %00000000_00000000_00000010_00000000
.WORD %00000000_00000000_00000001_00000000
.WORD %00000000_00000000_00000000_10000000
.WORD %00000000_00000000_00000000_01000000
.WORD %00000000_00000000_00000000_00100000
.WORD %00000000_00000000_00000000_00010000
.WORD %00000000_00000000_00000000_00001000
.WORD %00000000_00000000_00000000_00000100
.WORD %00000000_00000000_00000000_00000010
.WORD %00000000_00000000_00000000_00000001
PUTMPIXEL:
LOADC 1
; set a pixel in fb memory
; parameters: x,y,color - coordinates, color value (0-15)
PUTPIXEL:
PUTPIXEL_4BPP:
.EQU PUTPIXEL_X 0
.EQU PUTPIXEL_Y 4
.EQU PUTPIXEL_COLOR 8
.EQU PUTPIXEL_PIXPOS 12
.EQU PUTPIXEL_BPSAV 12
.EQU PUTPIXEL_FS 16
FPADJ -PUTPIXEL_FS
STORE PUTPIXEL_COLOR
STORE PUTPIXEL_Y
STORE PUTPIXEL_X
LOADREG BP
STORE PUTPIXEL_BPSAV
LOADC 0
STOREREG BP
; calculate vmem address: (x / 8) + (y * 80)
LOAD PUTPIXEL_X
@ -826,83 +750,37 @@ PUTPIXEL_4BPP:
ADD ; add results together for vmem addr
LOADCP FB_WA
OVER
STOREI ; store to framebuffer write addr register
DROP
LOADCP FB_RA ; and to framebuffer read addr register
SWAP ; swap addr and value for STOREI
STOREI
DROP
LOAD PUTPIXEL_X
; |0000.0000|0000.0000|0000.0000|0000.1111|
LOADC 7
AND ; calculate pixel position in word
LOADC 7
SWAP
SUB ; pixpos = 7 - (x & 7)
STORE PUTPIXEL_PIXPOS
DUP
STORE.B FB_WA ; set as write and read addresses
STORE.B FB_RA
; create pixel data from color value in
; leftmost pixel data bits (31-28)
LOADC 0
LOAD PUTPIXEL_COLOR
LOAD PUTPIXEL_PIXPOS
SHR ; rcount = pixpos / 2
ROTLOOP_:
DUP ; exit loop if rcount is 0
CBRANCH.Z ROTLOOP_END
SWAP ; pixel value is now on top of stack
BROT ; value = value << 8
SWAP ; rcount is now on top of stack
DEC 1 ; rcount = rcount - 1
BRANCH ROTLOOP_
ROTLOOP_END:
DROP ; drop rcount
; shifted pixel value is now at top of stack
LOAD PUTPIXEL_PIXPOS
LOADC 1
AND
CBRANCH.Z EVEN_PIXPOS
SHL 2 ; if pixpos is odd, shift by 4 bits
BPLC
SHL 2
EVEN_PIXPOS:
LOAD PUTPIXEL_X
; get bit value from x modulo 8
LOADC 7
AND
SHL 2 ; (x & 7) * 4 = offset into table
LOADCP INT_TO_MASK_TABLE
ADD
LOADI
SHL 2
STORE.B FB_SHIFTER ; store pixel into shifter
; read old vmem value
LOADCP FB_IO
LOADI
; mask bits
AND
; or in shifted pixel value
OR
LOAD PUTPIXEL_X ; use x coord as shift count
STORE.B FB_SHIFTCOUNT ; writing triggers shifting
; write new value
LOADCP FB_IO
SWAP
STOREI
DROP
LOAD.B FB_SHIFTERM ; get shift result as mask
NOT ; invert to get background mask
LOAD.B FB_IO ; get background pixel data
AND ; remove bits for new pixel from bg
LOAD.B FB_SHIFTER ; load shifted pixel
OR ; OR in new pixel bits
STORE.B FB_IO ; write new pixel data word to vmem
LOAD PUTPIXEL_BPSAV
STOREREG BP
FPADJ PUTPIXEL_FS
RET
.CPOOL
INT_TO_MASK_TABLE:
.WORD %00001111_11111111_11111111_11111111
.WORD %11110000_11111111_11111111_11111111
.WORD %11111111_00001111_11111111_11111111
.WORD %11111111_11110000_11111111_11111111
.WORD %11111111_11111111_00001111_11111111
.WORD %11111111_11111111_11110000_11111111
.WORD %11111111_11111111_11111111_00001111
.WORD %11111111_11111111_11111111_11110000
; draw a line between two points
; parameters: x0, y0, x1, y1, color
.EQU DL_X0 0