snake.asm

set [0x5000], 76
jsr genfood
set a, 0
set b, 0x8000
hwi 0
set i, 351
:_l8
set [i+0x8000], 0x4023
add i, 1
ifn i, 384
set pc, _l8
set i, 31
:_l7
set [i+0x8000], 0x4023
add i, 32
ifn i, 415
set pc, _l7
set i, 0
:_l5
set [i+0x8000], 0x4023
add i, 1
ifn i, 32
set pc, _l5
set i, 0
:_l6
set [i+0x8000], 0x4023
add i, 32
ifn i, 384
set pc, _l6
:_l0
set a, 1
hwi 1
set a, [dir]
ife c, 0x0080
set [dir], 65504
ife c, 0x0081
set [dir], 32
ife c, 0x0082
set [dir], 65535
ife c, 0x0083
set [dir], 1
set b, a
add b, [dir]
ife b, 0
set [dir], a
ifn [snakel], [snakelength]
add [snakel], 1
set i, [snakel]
add i, 0x5000
set j, [i]
add j, 0x8000
ifn j, 0x8000
set [j], 0
:_l1
set [i], [i+0xFFFF]
sub i, 1
ife i, 0x5000
set pc, _b1
set pc, _l1
:_b1
add [0x5000], [dir]
set a, [0x5000]
set b, a
mod b, 32
ife b, 0
set pc, die
ife b, 31
set pc, die
set b, a
div b, 32
ife b, 0
set pc, die
ife b, 11
set pc, die
set i, 0x5000
add i, [snakel]
:_l2
ife a, [i]
set pc, die
sub i, 1
ife i, 0x5000
set pc, _b2
set pc, _l2
:_b2
ifn a, [food]
set pc, _e0
add [snakelength], 1
jsr genfood
:_e0
set a, [0x5000]
add a, 0x8000
set [a], 0xA053
jsr wait
set pc, _l0
:wait
set i, 0x00FF
:_l4
ife i, 0
set pc, pop
sub i, 1
set pc, _l4
:rand
set a, [t]
set b, a
xor a, [0x5000]
add a, [snakelength]
set b, a
mod b, 0x180
set b, [b+0x8000]
add b, 1
mul a, b
set c, a
shl c, 8
shr a, 8
bor a, c
set [t], a
set z, a
set pc, pop
:die
set i, 0x8000
:_l3
jsr rand
set [i], z
add i, 1
ife i, 0x8180
set i, 0x8000
set pc, _l3
:genfood
jsr rand
mod z, 384
set x, z
mod x, 32
set y, z
div y, 32
ife x, 0
add z, 1
ife x, 31
sub z, 1
ife y, 0
add z, 32
ife y, 11
sub z, 32
set [food], z
add z, 0x8000
set [z], 0x504f
set pc, pop
:snakelength
dat 2
:snakel
dat 0
:food
dat 0x6000
:dir
dat 0x0001
:t
dat 0xAC71DCF1