; Bitmap pixel graphics routines for the CommanderX16 ; Custom routines to use the full-screen 640x480 and 320x240 screen modes. ; (These modes are not supported by the documented GRAPH_xxxx kernal routines) ; ; No text layer is currently shown, text can be drawn as part of the bitmap itself. ; Note: for similar graphics routines that also work on the C-64, use the "graphics" module instead. ; Note: for identical routines for a monochrome 1 bpp screen, use the "monogfx" module instead. ; Note: for color palette manipulation, use the "palette" module or write Vera registers yourself. ; Note: this library implements code for various resolutions and color depths. This takes up memory. ; If you're memory constrained you should probably not use this built-in library, ; but make a copy in your project only containing the code for the required resolution. ; ; NOTE: For sake of speed, NO BOUNDS CHECKING is performed in most routines! ; You'll have to make sure yourself that you're not writing outside of bitmap boundaries! ; ; ; SCREEN MODE LIST: ; mode 0 = reset back to default text mode ; mode 1 = bitmap 320 x 240 x 256c (8 bpp) ; mode 2 = bitmap 640 x 480 x 4c (2 bpp) ; mode 3 = bitmap 320 x 240 x 4c (not yet implemented: just use 256c, there's enough vram for that) ; mode 4 = bitmap 320 x 240 x 16c (not yet implemented: just use 256c, there's enough vram for that) ; mode 5 = bitmap 640 x 400 x 16c (not yet implemented) gfx2 { %option ignore_unused ; read-only control variables: ubyte active_mode = 0 uword width = 0 uword height = 0 ubyte bpp = 0 sub screen_mode(ubyte mode) { cx16.VERA_CTRL=0 when mode { 1 -> { ; lores 256c cx16.VERA_DC_VIDEO = (cx16.VERA_DC_VIDEO & %11001111) | %00100000 ; enable only layer 1 cx16.VERA_DC_HSCALE = 64 cx16.VERA_DC_VSCALE = 64 cx16.VERA_L1_CONFIG = %00000111 cx16.VERA_L1_MAPBASE = 0 cx16.VERA_L1_TILEBASE = 0 } 2 -> { ; highres 4c cx16.VERA_DC_VIDEO = (cx16.VERA_DC_VIDEO & %11001111) | %00100000 ; enable only layer 1 cx16.VERA_DC_HSCALE = 128 cx16.VERA_DC_VSCALE = 128 cx16.VERA_L1_CONFIG = %00000101 cx16.VERA_L1_MAPBASE = 0 cx16.VERA_L1_TILEBASE = %00000001 } else -> { ; back to default text mode cx16.r15L = cx16.VERA_DC_VIDEO & %00000111 ; retain chroma + output mode cbm.CINT() cx16.VERA_DC_VIDEO = (cx16.VERA_DC_VIDEO & %11111000) | cx16.r15L } } init_mode(mode) if active_mode clear_screen(0) } sub init_mode(ubyte mode) { ; set the internal configuration variables corresponding to the given screenmode ; doesn't manipulate Vera / the actual display mode active_mode = mode when mode { 1 -> { width = 320 height = 240 bpp = 8 } 2 -> { width = 640 height = 480 bpp = 2 } else -> { width = 0 height = 0 bpp = 0 active_mode = 0 } } } sub clear_screen(ubyte color) { position(0, 0) when active_mode { 1 -> { ; lores 256c repeat 240/2 cs_innerloop640(color) } 2 -> { ; highres 4c ubyte[] colors = [%00000000, %01010101, %10101010, %11111111] color = colors[color&3] repeat 480/4 cs_innerloop640(color) } } position(0, 0) } sub rect(uword xx, uword yy, uword rwidth, uword rheight, ubyte color) { if rwidth==0 or rheight==0 return horizontal_line(xx, yy, rwidth, color) if rheight==1 return horizontal_line(xx, yy+rheight-1, rwidth, color) vertical_line(xx, yy+1, rheight-2, color) if rwidth==1 return vertical_line(xx+rwidth-1, yy+1, rheight-2, color) } sub fillrect(uword xx, uword yy, uword rwidth, uword rheight, ubyte color) { ; Draw a filled rectangle of the given size and color. ; To fill the whole screen, use clear_screen(color) instead - it is much faster. if rwidth==0 return repeat rheight { horizontal_line(xx, yy, rwidth, color) yy++ } } sub horizontal_line(uword xx, uword yy, uword length, ubyte color) { if length==0 return when active_mode { 1 -> { ; lores 256c position(xx, yy) %asm {{ lda p8v_color ldx p8v_length+1 beq + ldy #0 - sta cx16.VERA_DATA0 iny bne - dex bne - + ldy p8v_length ; remaining beq + - sta cx16.VERA_DATA0 dey bne - + }} } 2 -> { ; highres 4c ....also mostly usable for lores 4c? color &= 3 ubyte[4] colorbits ubyte ii for ii in 3 downto 0 { colorbits[ii] = color color <<= 2 } void addr_mul_24_for_highres_4c(yy, xx) ; 24 bits result is in r0 and r1L (highest byte) %asm {{ lda cx16.VERA_ADDR_H and #%00000111 ; no auto advance sta cx16.VERA_ADDR_H stz cx16.VERA_CTRL ; setup vera addr 0 lda cx16.r1 and #1 sta cx16.VERA_ADDR_H lda cx16.r0 sta cx16.VERA_ADDR_L lda cx16.r0+1 sta cx16.VERA_ADDR_M ldx p8v_xx }} repeat length { %asm {{ txa and #3 tay lda cx16.VERA_DATA0 and p8b_gfx2.p8s_plot.p8v_mask4c,y ora p8v_colorbits,y sta cx16.VERA_DATA0 cpy #%00000011 ; next vera byte? bne ++ inc cx16.VERA_ADDR_L bne ++ inc cx16.VERA_ADDR_M + bne + inc cx16.VERA_ADDR_H + inx ; next pixel }} } } } } sub safe_horizontal_line(uword xx, uword yy, uword length, ubyte color) { ; does bounds checking and clipping if msb(yy)&$80!=0 or yy>=height return if msb(xx)&$80!=0 { length += xx xx = 0 } if xx>=width return if xx+length>width length = width-xx if length>width return horizontal_line(xx, yy, length, color) } sub vertical_line(uword xx, uword yy, uword lheight, ubyte color) { when active_mode { 1 -> { ; lores 256c ; set vera auto-increment to 320 pixel increment (=next line) position(xx,yy) cx16.VERA_ADDR_H = cx16.VERA_ADDR_H & %00000111 | (14<<4) %asm {{ ldy p8v_lheight beq + lda p8v_color - sta cx16.VERA_DATA0 dey bne - + }} } 2 -> { ; highres 4c ; use TWO vera adress pointers simultaneously one for reading, one for writing, so auto-increment is possible if lheight==0 return position2(xx,yy,true) set_both_strides(13) ; 160 increment = 1 line in 640 px 4c mode ;; color &= 3 ;; color <<= gfx2.plot.shift4c[lsb(xx) & 3] cx16.r2L = lsb(xx) & 3 when color & 3 { 1 -> color = gfx2.plot.shiftedleft_4c_1[cx16.r2L] 2 -> color = gfx2.plot.shiftedleft_4c_2[cx16.r2L] 3 -> color = gfx2.plot.shiftedleft_4c_3[cx16.r2L] } ubyte @shared mask = gfx2.plot.mask4c[lsb(xx) & 3] repeat lheight { %asm {{ lda cx16.VERA_DATA0 and p8v_mask ora p8v_color sta cx16.VERA_DATA1 }} } } } sub set_both_strides(ubyte stride) { stride <<= 4 cx16.VERA_CTRL = 0 cx16.VERA_ADDR_H = cx16.VERA_ADDR_H & %00000111 | stride cx16.VERA_CTRL = 1 cx16.VERA_ADDR_H = cx16.VERA_ADDR_H & %00000111 | stride } } sub line(uword @zp x1, uword @zp y1, uword @zp x2, uword @zp y2, ubyte color) { ; Bresenham algorithm. ; This code special-cases various quadrant loops to allow simple ++ and -- operations. if y1>y2 { ; make sure dy is always positive to have only 4 instead of 8 special cases cx16.r0 = x1 x1 = x2 x2 = cx16.r0 cx16.r0 = y1 y1 = y2 y2 = cx16.r0 } word @zp dx = (x2 as word)-x1 word @zp dy = (y2 as word)-y1 if dx==0 { vertical_line(x1, y1, abs(dy) as uword +1, color) return } if dy==0 { if x1>x2 x1=x2 horizontal_line(x1, y1, abs(dx) as uword +1, color) return } word @zp d = 0 cx16.r1L = true ; 'positive_ix' if dx < 0 { dx = -dx cx16.r1L = false } word @zp dx2 = dx*2 word @zp dy2 = dy*2 cx16.r14 = x1 ; internal plot X if dx >= dy { if cx16.r1L { repeat { plot(cx16.r14, y1, color) if cx16.r14==x2 return cx16.r14++ d += dy2 if d > dx { y1++ d -= dx2 } } } else { repeat { plot(cx16.r14, y1, color) if cx16.r14==x2 return cx16.r14-- d += dy2 if d > dx { y1++ d -= dx2 } } } } else { if cx16.r1L { repeat { plot(cx16.r14, y1, color) if y1 == y2 return y1++ d += dx2 if d > dy { cx16.r14++ d -= dy2 } } } else { repeat { plot(cx16.r14, y1, color) if y1 == y2 return y1++ d += dx2 if d > dy { cx16.r14-- d -= dy2 } } } } } sub circle(uword @zp xcenter, uword @zp ycenter, ubyte radius, ubyte color) { ; Warning: NO BOUNDS CHECKS. Make sure circle fits in the screen. ; Midpoint algorithm. if radius==0 return ubyte @zp xx = radius ubyte @zp yy = 0 word @zp decisionOver2 = (1 as word)-xx ; R14 = internal plot X ; R15 = internal plot Y while xx>=yy { cx16.r14 = xcenter + xx cx16.r15 = ycenter + yy plotq() cx16.r14 = xcenter - xx plotq() cx16.r14 = xcenter + xx cx16.r15 = ycenter - yy plotq() cx16.r14 = xcenter - xx plotq() cx16.r14 = xcenter + yy cx16.r15 = ycenter + xx plotq() cx16.r14 = xcenter - yy plotq() cx16.r14 = xcenter + yy cx16.r15 = ycenter - xx plotq() cx16.r14 = xcenter - yy plotq() yy++ if decisionOver2>=0 { xx-- decisionOver2 -= xx*$0002 } decisionOver2 += yy*$0002 decisionOver2++ } sub plotq() { ; cx16.r14 = x, cx16.r15 = y, color=color. plot(cx16.r14, cx16.r15, color) } } sub safe_circle(uword @zp xcenter, uword @zp ycenter, ubyte radius, ubyte color) { ; This version does bounds checks and clipping, but is a lot slower. ; Midpoint algorithm. if radius==0 return ubyte @zp xx = radius ubyte @zp yy = 0 word @zp decisionOver2 = (1 as word)-xx ; R14 = internal plot X ; R15 = internal plot Y while xx>=yy { cx16.r14 = xcenter + xx cx16.r15 = ycenter + yy plotq() cx16.r14 = xcenter - xx plotq() cx16.r14 = xcenter + xx cx16.r15 = ycenter - yy plotq() cx16.r14 = xcenter - xx plotq() cx16.r14 = xcenter + yy cx16.r15 = ycenter + xx plotq() cx16.r14 = xcenter - yy plotq() cx16.r14 = xcenter + yy cx16.r15 = ycenter - xx plotq() cx16.r14 = xcenter - yy plotq() yy++ if decisionOver2>=0 { xx-- decisionOver2 -= xx*$0002 } decisionOver2 += yy*$0002 decisionOver2++ } sub plotq() { ; cx16.r14 = x, cx16.r15 = y, color=color. safe_plot(cx16.r14, cx16.r15, color) } } sub disc(uword @zp xcenter, uword @zp ycenter, ubyte @zp radius, ubyte color) { ; Warning: NO BOUNDS CHECKS. Make sure circle fits in the screen. ; Midpoint algorithm, filled if radius==0 return ubyte @zp yy = 0 word @zp decisionOver2 = (1 as word)-radius while radius>=yy { horizontal_line(xcenter-radius, ycenter+yy, radius*$0002+1, color) horizontal_line(xcenter-radius, ycenter-yy, radius*$0002+1, color) horizontal_line(xcenter-yy, ycenter+radius, yy*$0002+1, color) horizontal_line(xcenter-yy, ycenter-radius, yy*$0002+1, color) yy++ if decisionOver2>=0 { radius-- decisionOver2 -= radius*$0002 } decisionOver2 += yy*$0002 decisionOver2++ } } sub safe_disc(uword @zp xcenter, uword @zp ycenter, ubyte @zp radius, ubyte color) { ; This version does bounds checks and clipping, but is a lot slower. ; Midpoint algorithm, filled if radius==0 return ubyte @zp yy = 0 word @zp decisionOver2 = (1 as word)-radius while radius>=yy { safe_horizontal_line(xcenter-radius, ycenter+yy, radius*$0002+1, color) safe_horizontal_line(xcenter-radius, ycenter-yy, radius*$0002+1, color) safe_horizontal_line(xcenter-yy, ycenter+radius, yy*$0002+1, color) safe_horizontal_line(xcenter-yy, ycenter-radius, yy*$0002+1, color) yy++ if decisionOver2>=0 { radius-- decisionOver2 -= radius*$0002 } decisionOver2 += yy*$0002 decisionOver2++ } } sub plot(uword @zp xx, uword @zp yy, ubyte @zp color) { ubyte[4] @shared mask4c = [%00111111, %11001111, %11110011, %11111100] ubyte[4] @shared shift4c = [6,4,2,0] ubyte[4] shiftedleft_4c_1 = [1<<6, 1<<4, 1<<2, 1<<0] ubyte[4] shiftedleft_4c_2 = [2<<6, 2<<4, 2<<2, 2<<0] ubyte[4] shiftedleft_4c_3 = [3<<6, 3<<4, 3<<2, 3<<0] when active_mode { 1 -> { ; lores 256c void addr_mul_24_for_lores_256c(yy, xx) ; 24 bits result is in r0 and r1L (highest byte) %asm {{ stz cx16.VERA_CTRL lda cx16.r1 ora #%00010000 ; enable auto-increment so next_pixel() can be used after this sta cx16.VERA_ADDR_H lda cx16.r0+1 sta cx16.VERA_ADDR_M lda cx16.r0 sta cx16.VERA_ADDR_L lda p8v_color sta cx16.VERA_DATA0 }} } 2 -> { ; highres 4c ....also mostly usable for lores 4c? void addr_mul_24_for_highres_4c(yy, xx) ; 24 bits result is in r0 and r1L (highest byte) cx16.r2L = lsb(xx) & 3 ; xbits ; color &= 3 ; color <<= shift4c[cx16.r2L] when color & 3 { 1 -> color = shiftedleft_4c_1[cx16.r2L] 2 -> color = shiftedleft_4c_2[cx16.r2L] 3 -> color = shiftedleft_4c_3[cx16.r2L] } %asm {{ stz cx16.VERA_CTRL lda cx16.r1L sta cx16.VERA_ADDR_H lda cx16.r0H sta cx16.VERA_ADDR_M lda cx16.r0L sta cx16.VERA_ADDR_L ldy cx16.r2L ; xbits lda p8v_mask4c,y and cx16.VERA_DATA0 ora p8v_color sta cx16.VERA_DATA0 }} } } } sub safe_plot(uword xx, uword yy, ubyte color) { ; A plot that does bounds checks to see if the pixel is inside the screen. if msb(xx)&$80!=0 or msb(yy)&$80!=0 return if xx >= width or yy >= height return plot(xx, yy, color) } sub pget(uword @zp xx, uword yy) -> ubyte { when active_mode { 1 -> { ; lores 256c void addr_mul_24_for_lores_256c(yy, xx) ; 24 bits result is in r0 and r1L (highest byte) %asm {{ stz cx16.VERA_CTRL lda cx16.r1 sta cx16.VERA_ADDR_H lda cx16.r0+1 sta cx16.VERA_ADDR_M lda cx16.r0 sta cx16.VERA_ADDR_L lda cx16.VERA_DATA0 }} } 2 -> { ; hires 4c void addr_mul_24_for_highres_4c(yy, xx) ; 24 bits result is in r0 and r1L (highest byte) %asm {{ stz cx16.VERA_CTRL lda cx16.r1L sta cx16.VERA_ADDR_H lda cx16.r0H sta cx16.VERA_ADDR_M lda cx16.r0L sta cx16.VERA_ADDR_L lda cx16.VERA_DATA0 pha lda p8v_xx and #3 tay lda p8b_gfx2.p8s_plot.p8v_shift4c,y tay pla cpy #0 beq + - lsr a dey bne - + and #3 }} } else -> return 0 } } sub fill(uword x, uword y, ubyte new_color) { ; Non-recursive scanline flood fill. ; based loosely on code found here https://www.codeproject.com/Articles/6017/QuickFill-An-efficient-flood-fill-algorithm ; with the fixes applied to the seedfill_4 routine as mentioned in the comments. const ubyte MAXDEPTH = 64 word @zp xx = x as word word @zp yy = y as word word[MAXDEPTH] @split @shared stack_xl word[MAXDEPTH] @split @shared stack_xr word[MAXDEPTH] @split @shared stack_y byte[MAXDEPTH] @shared stack_dy cx16.r12L = 0 ; stack pointer word x1 word x2 byte dy cx16.r10L = new_color sub push_stack(word sxl, word sxr, word sy, byte sdy) { if cx16.r12L==MAXDEPTH return cx16.r0s = sy+sdy if cx16.r0s>=0 and cx16.r0s<=height-1 { ;; stack_xl[cx16.r12L] = sxl ;; stack_xr[cx16.r12L] = sxr ;; stack_y[cx16.r12L] = sy ;; stack_dy[cx16.r12L] = sdy ;; cx16.r12L++ %asm {{ ldy cx16.r12L lda p8v_sxl sta p8v_stack_xl_lsb,y lda p8v_sxl+1 sta p8v_stack_xl_msb,y lda p8v_sxr sta p8v_stack_xr_lsb,y lda p8v_sxr+1 sta p8v_stack_xr_msb,y lda p8v_sy sta p8v_stack_y_lsb,y lda p8v_sy+1 sta p8v_stack_y_msb,y ldy cx16.r12L lda p8v_sdy sta p8v_stack_dy,y inc cx16.r12L }} } } sub pop_stack() { ;; cx16.r12L-- ;; x1 = stack_xl[cx16.r12L] ;; x2 = stack_xr[cx16.r12L] ;; y = stack_y[cx16.r12L] ;; dy = stack_dy[cx16.r12L] %asm {{ dec cx16.r12L ldy cx16.r12L lda p8v_stack_xl_lsb,y sta p8v_x1 lda p8v_stack_xl_msb,y sta p8v_x1+1 lda p8v_stack_xr_lsb,y sta p8v_x2 lda p8v_stack_xr_msb,y sta p8v_x2+1 lda p8v_stack_y_lsb,y sta p8v_yy lda p8v_stack_y_msb,y sta p8v_yy+1 ldy cx16.r12L lda p8v_stack_dy,y sta p8v_dy }} yy+=dy } cx16.r11L = pget(xx as uword, yy as uword) ; old_color if cx16.r11L == cx16.r10L return if xx<0 or xx>width-1 or yy<0 or yy>height-1 return push_stack(xx, xx, yy, 1) push_stack(xx, xx, yy + 1, -1) word left = 0 while cx16.r12L { pop_stack() xx = x1 ; possible speed optimization: if mode==1 (256c) use vera autodecrement instead of pget(), but code bloat not worth it? while xx >= 0 { if pget(xx as uword, yy as uword) != cx16.r11L break xx-- } if x1!=xx horizontal_line(xx as uword+1, yy as uword, x1-xx as uword, cx16.r10L) else goto skip left = xx + 1 if left < x1 push_stack(left, x1 - 1, yy, -dy) xx = x1 + 1 do { cx16.r9 = xx ; possible speed optimization: if mode==1 (256c) use vera autoincrement instead of pget(), but code bloat not worth it? while xx <= width-1 { if pget(xx as uword, yy as uword) != cx16.r11L break xx++ } if cx16.r9!=xx horizontal_line(cx16.r9, yy as uword, (xx as uword)-cx16.r9, cx16.r10L) push_stack(left, xx - 1, yy, dy) if xx > x2 + 1 push_stack(x2 + 1, xx - 1, yy, -dy) skip: xx++ while xx <= x2 { if pget(xx as uword, yy as uword) == cx16.r11L break xx++ } left = xx } until xx>x2 } } sub position(uword @zp xx, uword yy) { when active_mode { 1 -> { ; lores 256c void addr_mul_24_for_lores_256c(yy, xx) ; 24 bits result is in r0 and r1L (highest byte) } 2 -> { ; highres 4c void addr_mul_24_for_highres_4c(yy, xx) ; 24 bits result is in r0 and r1L (highest byte) } } cx16.r2L = cx16.r1L cx16.vaddr(cx16.r2L, cx16.r0, 0, 1) } sub position2(uword @zp xx, uword yy, bool also_port_1) { position(xx, yy) if also_port_1 cx16.vaddr_clone(0) } inline asmsub next_pixel(ubyte color @A) { ; -- sets the next pixel byte to the graphics chip. ; for 8 bpp screens this will plot 1 pixel. ; for 2 bpp screens it will plot 4 pixels at once (color = bit pattern). %asm {{ sta cx16.VERA_DATA0 }} } asmsub next_pixels(uword pixels @AY, uword amount @R0) clobbers(A, X, Y) { ; -- sets the next bunch of pixels from a prepared array of bytes. ; for 8 bpp screens this will plot 1 pixel per byte. ; for 2 bpp screens it will plot 4 pixels at once (colors are the bit patterns per byte). %asm {{ sta P8ZP_SCRATCH_W1 sty P8ZP_SCRATCH_W1+1 ldx cx16.r0+1 beq + ldy #0 - lda (P8ZP_SCRATCH_W1),y sta cx16.VERA_DATA0 iny bne - inc P8ZP_SCRATCH_W1+1 ; next page of 256 pixels dex bne - + ldx cx16.r0 ; remaining pixels beq + ldy #0 - lda (P8ZP_SCRATCH_W1),y sta cx16.VERA_DATA0 iny dex bne - + rts }} } asmsub set_8_pixels_from_bits(ubyte bits @R0, ubyte oncolor @A, ubyte offcolor @Y) clobbers(X) { ; this is only useful in 256 color mode where one pixel equals one byte value. %asm {{ ldx #8 - asl cx16.r0 bcc + sta cx16.VERA_DATA0 bra ++ + sty cx16.VERA_DATA0 + dex bne - rts }} } const ubyte charset_bank = $1 const uword charset_addr = $f000 ; in bank 1, so $1f000 sub text_charset(ubyte charset) { ; -- select the text charset to use with the text() routine ; the charset number is the same as for the cx16.screen_set_charset() ROM function. ; 1 = ISO charset, 2 = PETSCII uppercase+graphs, 3= PETSCII uppercase+lowercase. cx16.screen_set_charset(charset, 0) } sub text(uword @zp xx, uword yy, ubyte color, uword sctextptr) { ; -- Write some text at the given pixel position. The text string must be in screencode encoding (not petscii!). ; You must also have called text_charset() first to select and prepare the character set to use. uword chardataptr ubyte[8] @shared char_bitmap_bytes_left ubyte[8] @shared char_bitmap_bytes_right when active_mode { 1 -> { ; lores 256c while @(sctextptr) { chardataptr = charset_addr + (@(sctextptr) as uword)*8 cx16.vaddr(charset_bank, chardataptr, 1, 1) repeat 8 { position(xx,yy) yy++ %asm {{ ldx p8v_color lda cx16.VERA_DATA1 sta P8ZP_SCRATCH_B1 ldy #8 - asl P8ZP_SCRATCH_B1 bcc + stx cx16.VERA_DATA0 ; write a pixel bra ++ + lda cx16.VERA_DATA0 ; don't write a pixel, but do advance to the next address + dey bne - }} } xx+=8 yy-=8 sctextptr++ } } 2 -> { ; hires 4c ; we're going to use a few cx16 registers to make sure every variable is in zeropage in the inner loop. cx16.r11L = color while @(sctextptr) { chardataptr = charset_addr + (@(sctextptr) as uword)*8 cx16.vaddr(charset_bank, chardataptr, 1, true) ; for reading the chardata from Vera data channel 1 position(xx, yy) ; only calculated once, we update vera address in the loop instead cx16.VERA_ADDR_H &= $0f ; no auto increment repeat 8 { cx16.r10L = cx16.VERA_DATA1 ; get the next 8 horizontal character bits cx16.r7 = xx repeat 8 { cx16.r10L <<= 1 if_cs { cx16.r2L = cx16.r7L & 3 ; xbits when cx16.r11L & 3 { 1 -> cx16.r12L = gfx2.plot.shiftedleft_4c_1[cx16.r2L] 2 -> cx16.r12L = gfx2.plot.shiftedleft_4c_2[cx16.r2L] 3 -> cx16.r12L = gfx2.plot.shiftedleft_4c_3[cx16.r2L] else -> cx16.r12L = 0 } cx16.VERA_DATA0 = cx16.VERA_DATA0 & gfx2.plot.mask4c[cx16.r2L] | cx16.r12L } cx16.r7++ if (cx16.r7 & 3) == 0 { ; increment the pixel address by one %asm {{ stz cx16.VERA_CTRL clc lda cx16.VERA_ADDR_L adc #1 sta cx16.VERA_ADDR_L lda cx16.VERA_ADDR_M adc #0 sta cx16.VERA_ADDR_M lda cx16.VERA_ADDR_H adc #0 sta cx16.VERA_ADDR_H }} } } ; increment pixel address to the next line %asm {{ stz cx16.VERA_CTRL clc lda cx16.VERA_ADDR_L adc #(640-8)/4 sta cx16.VERA_ADDR_L lda cx16.VERA_ADDR_M adc #0 sta cx16.VERA_ADDR_M lda cx16.VERA_ADDR_H adc #0 sta cx16.VERA_ADDR_H }} } xx+=8 sctextptr++ } } } } asmsub cs_innerloop640(ubyte color @A) clobbers(Y) { ; using verafx 32 bits writes here would make this faster but it's safer to ; use verafx only explicitly when you know what you're doing. %asm {{ ldy #80 - sta cx16.VERA_DATA0 sta cx16.VERA_DATA0 sta cx16.VERA_DATA0 sta cx16.VERA_DATA0 sta cx16.VERA_DATA0 sta cx16.VERA_DATA0 sta cx16.VERA_DATA0 sta cx16.VERA_DATA0 dey bne - rts }} } asmsub addr_mul_24_for_highres_4c(uword yy @R2, uword xx @R3) clobbers(A, Y) -> uword @R0, uword @R1 { ; yy * 160 + xx/4 (24 bits calculation) ; 24 bits result is in r0 and r1L (highest byte) %asm {{ ldy #5 - asl cx16.r2 rol cx16.r2+1 dey bne - lda cx16.r2 sta cx16.r0 lda cx16.r2+1 sta cx16.r0+1 asl cx16.r0 rol cx16.r0+1 asl cx16.r0 rol cx16.r0+1 ; xx >>= 2 (xx=R3) lsr cx16.r3+1 ror cx16.r3 lsr cx16.r3+1 ror cx16.r3 ; add r2 and xx (r3) to r0 (24-bits) stz cx16.r1 clc lda cx16.r0 adc cx16.r2 sta cx16.r0 lda cx16.r0+1 adc cx16.r2+1 sta cx16.r0+1 bcc + inc cx16.r1 + clc lda cx16.r0 adc cx16.r3 sta cx16.r0 lda cx16.r0+1 adc cx16.r3+1 sta cx16.r0+1 bcc + inc cx16.r1 + rts }} } asmsub addr_mul_24_for_lores_256c(uword yy @R0, uword xx @AY) clobbers(A) -> uword @R0, ubyte @R1 { ; yy * 320 + xx (24 bits calculation) %asm {{ sta P8ZP_SCRATCH_W1 sty P8ZP_SCRATCH_W1+1 lda cx16.r0 sta P8ZP_SCRATCH_B1 lda cx16.r0+1 sta cx16.r1 sta P8ZP_SCRATCH_REG lda cx16.r0 asl a rol P8ZP_SCRATCH_REG asl a rol P8ZP_SCRATCH_REG asl a rol P8ZP_SCRATCH_REG asl a rol P8ZP_SCRATCH_REG asl a rol P8ZP_SCRATCH_REG asl a rol P8ZP_SCRATCH_REG sta cx16.r0 lda P8ZP_SCRATCH_B1 clc adc P8ZP_SCRATCH_REG sta cx16.r0+1 bcc + inc cx16.r1 + ; now add the value to this 24-bits number lda cx16.r0 clc adc P8ZP_SCRATCH_W1 sta cx16.r0 lda cx16.r0+1 adc P8ZP_SCRATCH_W1+1 sta cx16.r0+1 bcc + inc cx16.r1 + lda cx16.r1 rts }} } }