94 lines
3.2 KiB
NASM
94 lines
3.2 KiB
NASM
;; input m0[0] start address
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;; [X ] [Y ] [D1 ]
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;; mov 0,ct0
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;; mov mc0,ra0
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;; variables:
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;; m0[0]
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;; m0[1] dma read value (local); post-shift 4-byte remainder (global)
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;; m0[2] saved accumulator (global)
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setup:
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;; [X ] [Y ] [D1 ]
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mov 1,ct0
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mov 0,ct3
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mov 0,mc0
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mov 0,mc0
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mvi parse_base10,pc
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mov 1,lop
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;; parse_base10 return
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mov all,mc3
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mvi parse_base10,pc
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mov 1,lop
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;; parse_base10 return
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mov all,mc3
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nop
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nop
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nop
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parse_base10:
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;; [X ] [Y ] [D1 ]
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mov 1,ct0
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mov m0,p mov m0,a
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add
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jmp nz,parse_loop
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clr a ; delay slot
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dma_next_chunk:
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;; dma d0,mc0,1
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;; begin fake number 0x39322033 "92 3"
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mvi 0x393220,pl
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add mov alu,a mov 0x33,pl
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rl8 mov alu,a mov 1,ct0
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add mov all,mc0
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;; end fake number
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end_dma_next_chunk:
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parse_loop:
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;; extract first (leftmost) digit
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mov 1,ct0
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mov mc0,a mov 0x7f,pl
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or
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jmp s,end_of_input
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rl8 mov alu,a mov 10,rx ; m0[2] 0x00000000
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jmp z,dma_next_chunk
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and mov m0,y mov all,pl
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;; MUL: post-multiplication accumulator
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;; P: post-mask digit
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;; A: pre-xor string
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mov 1,ct0
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xor clr a mov all,mc0 ; m0[1] 0x20323300
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add mov alu,a mov 0x30,pl ; 0x30 ascii '0'
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;; A: post-mask digit
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;;
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sub mov alu,a mov 10,pl
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;; if ((0x39 - 0x30) < 0) goto non_digit;
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jmp s,non_digit
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;; possibly set S flag for `jmp ns,non_digit`
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sub mov 2,ct0 ; sub in delay slot
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;; if (((0x39 - 0x30) - 10) >= 0) goto non_digit;
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jmp ns,non_digit
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mov mul,p mov 2,ct0 ; mov in delay slot
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;; P: accumulator * 10 result
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digit:
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;; we have a valid digit; add it to the accumulator; save to m0[2]
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;; [X ] [Y ] [D1 ]
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jmp parse_loop
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add mov all,mc0 ; add in delay slot ; m0[2] 0x00000009
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non_digit:
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;; this is not a valid digit; return and clear the accumulator as A
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;; [X ] [Y ] [D1 ]
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btm
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mov m0,a mov 0,mc0 ; clr in delay slot ; m0[2]
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;; m0:
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;; 00000000 32330000 00000009 0000000
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end_of_input:
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btm
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clr a
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