bilbo/saturn-examples
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

scu-dsp: add parse10 (incomplete)

Browse Source
This commit is contained in:
Zack Buhman 2025-08-09 22:10:21 -05:00
parent 4503b3542e
commit 55c38ebf5f
1 changed files with 73 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

73
scu-dsp/parse10.asm Normal file
View File

@ -0,0 +1,73 @@
;; input m0[0] start address
;; [X ] [Y ] [D1 ]
;; mov 0,ct0
;; mov mc0,ra0
;; variables:
;; m0[0] dma read start address (global)
;; m0[1] dma read value (local); post-shift 4-byte remainder (global)
;; m0[2] saved accumulator (global)
caller_setup:
mov 0,ct0
;; start address
mov mc0,ra0
mov 2,ct0
;; mov 0,mc0
parse_base10:
next_chunk:
clr a mov 1,ct0
;; dma d0,mc0,1
;; begin fake number 0x39322033 "92 3"
mvi 0x393220,pl
add mov alu,a mov 0x33,pl
rl8 mov alu,a
add mov all,mc0
;; end fake number
post_dma_load:
;; extract first (leftmost) digit
mov 1,ct0
mov mc0,a mov 0x7f,pl
rl8 mov alu,a ;;mov all,mc0 ; m0[1] 0x20323339
;; multiply saved accumulator by 10
;; [X ] [Y ] [D1 ]
mov m0,y mov 10,rx ; m0[2] 0x00000000
and mov all,pl
;; MUL: post-multiplication accumulator
;; P: post-mask digit
;; A: pre-xor string
mov 1,ct0
xor clr a mov all,mc0 ; m0[1] 0x20323300
;; FIXME: if 0x00 jump to "end of input"?
add mov alu,a mov 0x30,pl ; 0x30 ascii '0'
;; A: post-mask digit
;;
sub mov alu,a mov 10,pl
;; if ((0x39 - 0x30) < 0) goto non_digit;
jmp s,non_digit
;; possibly set S flag for `jmp ns,non_digit`
sub ; sub in delay slot
;; if (((0x39 - 0x30) - 10) >= 0) goto non_digit;
jmp ns,non_digit
mov mul,p mov 2,ct0 ; mov in delay slot
;; P: accumulator * 10 result
digit:
;; we have a valid digit; add it to the accumulator; save to m0[2]
;; [X ] [Y ] [D1 ]
jmp post_dma_load
add mov all,mc0 ; add in delay slot ; m0[2] 0x00000009
non_digit:
;; this is not a valid digit; return the accumulator
;; [X ] [Y ] [D1 ]
btm
clr a ; clr in delay slot
;; m0:
;; 00000000 32330000 00000009 0000000