Trevor Merritt
e29ac45c84
scroll left and right work in stdef and hidef adds octo test roms adds schip fonts to memory
81 lines
1.1 KiB
Plaintext
81 lines
1.1 KiB
Plaintext
###########################################
|
|
#
|
|
# A modular stack data structure using
|
|
# a vf-based calling convention.
|
|
# This approach can only be extended up to
|
|
# a size 16 stack.
|
|
#
|
|
###########################################
|
|
|
|
: scratch 0 0 0 0 0 0 0 0
|
|
: under 0
|
|
: stack 0
|
|
: over 0 0 0 0 0 0 0
|
|
|
|
: push
|
|
# here we take our argument from vf.
|
|
# and do not corrupt any other registers.
|
|
# we can eliminate the scratch saving
|
|
# and restoring if low registers don't
|
|
# need to be preserved.
|
|
|
|
i := scratch
|
|
save v6
|
|
|
|
i := stack
|
|
load v6
|
|
i := over
|
|
save v6
|
|
i := stack
|
|
v0 := vf
|
|
save v0
|
|
|
|
i := scratch
|
|
load v6
|
|
;
|
|
|
|
: pop
|
|
# result is left in vf.
|
|
# again, we don't corrupt any other registers.
|
|
|
|
i := scratch
|
|
save v7
|
|
|
|
i := stack
|
|
load v7
|
|
vf := v0
|
|
i := under
|
|
save v7
|
|
|
|
i := scratch
|
|
load v7
|
|
;
|
|
|
|
###########################################
|
|
#
|
|
# Usage Example:
|
|
#
|
|
###########################################
|
|
|
|
: print
|
|
# takes an arg in vf
|
|
i := hex vf
|
|
sprite va vb 5
|
|
va += 6
|
|
;
|
|
|
|
: main
|
|
va := 3
|
|
vb := 3
|
|
|
|
vf := 5 push
|
|
vf := 3 push
|
|
vf := 1 push
|
|
pop print
|
|
vf := 9 push
|
|
pop print
|
|
pop print
|
|
pop print
|
|
|
|
# should print '1935'
|