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[entry: main]
[enable: logical_registers]
// Renders the Mandelbrot set as ASCII art. The evolving z value is kept in a
// Complex struct on the stack (accessed through its field offsets), while the
// per-pixel constant c stays in xmm2/xmm3. Uses double-precision floats and the
// logical_registers extension (r1..r14 name the general-purpose registers).
const SYS_WRITE = 1
const SYS_EXIT = 60
const STDOUT = 1
const W = 80
const H = 30
const MAX_ITER = 32
struct Complex
{
re: qword
im: qword
}
data palette = " .:-=+*#%@"
proc main
{
stack z[Complex.size]
stack row[W + 1]
r11 = 0 // py
row_loop:
// ci = py * 0.08 - 1.2
xmm3 = r11
xmm7 = 0.08
xmm3 *= xmm7
xmm7 = 1.2
xmm3 -= xmm7
r12 = 0 // px
col_loop:
// cr = px * 0.04375 - 2.5
xmm2 = r12
xmm7 = 0.04375
xmm2 *= xmm7
xmm7 = 2.5
xmm2 -= xmm7
// z = 0 + 0i
xmm0 = 0.0
r5 = z
r5 += Complex.re
^r5 = xmm0 // z.re = 0
r5 = z
r5 += Complex.im
^r5 = xmm0 // z.im = 0
r2 = 0 // iteration count
iter_loop:
// load z into xmm0 (zr) and xmm1 (zi)
r5 = z
r5 += Complex.re
xmm0 = ^r5
r5 = z
r5 += Complex.im
xmm1 = ^r5
// zr2 = zr*zr, zi2 = zi*zi
xmm4 = xmm0
xmm4 *= xmm0
xmm5 = xmm1
xmm5 *= xmm1
// escape when zr2 + zi2 > 4.0
xmm6 = xmm4
xmm6 += xmm5
if xmm6 > 4.0
goto plot
// new_zi = 2*zr*zi + ci (uses the old zr and zi)
xmm6 = xmm0
xmm6 *= xmm1
xmm6 += xmm6
xmm6 += xmm3
xmm7 = xmm6 // stash new_zi
// new_zr = zr2 - zi2 + cr
xmm4 -= xmm5
xmm4 += xmm2
// store the new z back into the struct
r5 = z
r5 += Complex.re
^r5 = xmm4 // z.re = new_zr
r5 = z
r5 += Complex.im
^r5 = xmm7 // z.im = new_zi
r2 += 1
if r2 < MAX_ITER
goto iter_loop
plot:
// index = iter * 9 / MAX_ITER, then char = palette[index]
r1 = r2
r1 *= 9
r3 = MAX_ITER
r1 /= r3
r5 = palette
r5 += r1
r4 = ^byte r5
r6 = row
r6 += r12
^byte r6 = r4
r12 += 1
if r12 < W
goto col_loop
// terminate the row with a newline and write it
r6 = row
r6 += W
r1 = 10
^byte r6 = r1
r1 = SYS_WRITE
r6 = STDOUT
r5 = row
r4 = W
r4 += 1
syscall
r11 += 1
if r11 < H
goto row_loop
r1 = SYS_EXIT
r6 = 0
syscall
}
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