crsn/examples/mandelbrot/mandelbrot-lowres.csn

(
    (sc-init 1024 768)
    (sc-opt SCREEN_AUTOBLIT 0)
    (sc-opt SCREEN_UPSCALE 8)
    (def W 128)
    (def H 96)
    (def MAXITER 50)
    
    (sym gradient r9)
    (sym asciigr r10)
    
    (mkbf gradient (
        0x421e0f 0x19071a 0x09012f 0x040449 0x000764 0x0c2c8a 0x1852b1 0x397dd1 
        0x86b5e5 0xd3ecf8 0xf1e9bf 0xf8c95f 0xffaa00 0xcc8000 0x995700 0x6a3403))
    
    (sym x r7)
    (sym y r8)
    (:row)
        (:col)
            (call pixel x y)
            (sub r0 MAXITER 1)
            (rcmp res0 1 r0
                (eq?
                    (mod r0 res0 16)
                    (bfrd r0 @gradient r0)
                )
                (else? (ld r0 0))
            )
            (sc-wr x y r0)
            (inc x)
            (cmp x W)
            (j.ne :col)
        (ld x 0)
        (inc y)
        (sc-blit) ; Render after every row
        (cmp y H)
        (j.ne :row)
    
    ;(sc-blit)
    
    (:slp)
    (sc-poll)
    (mslp 10)
    (j :slp)
    
    (proc pixel xi yi
        (sym x0 r7) 
        (sym y0 r8)
        (itf x0 xi)
        (itf y0 yi)
        
        ; Scale to the interesting range x -2.5..1 and y -1..1
        (itf r0 W)
        (itf r1 H)
        
        (fdiv x0 r0)
        (fmul x0 3.5)
        (fsub x0 2.5)
        
        (fdiv y0 r1)
        (fmul y0 2.4)
        (fsub y0 1.2)        
        
        (sym x r5)
        (sym y r6)
        (ld x 0.0)
        (ld y 0.0)
        (sym iter r4)
        
        (:iter)
            (cmp iter MAXITER)
            (j.eq :end)
            (fmul r0 x x)
            (fmul r1 y y)
            (fadd r2 r1)
            (fcmp r2 4.0)
            (j.gt :end)
            
            (fsub r2 r0 r1)
            (fadd r2 x0)
                    
            (fmul r0 x y)
            (fmul r0 2.0)        
            (fadd r0 y0)
            (ld y r0)        
            (ld x r2)
            (inc iter)
            (j :iter)
        
        (:end)
        (ret iter)
    )
)