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Ross Wilson
2016-03-16 15:20:54 +10:00
parent 8e9349b419
commit c7792d8273
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docs/blockpunch.asm Normal file
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; typed in from imlacdocs/blockpunchsrc.pdf
org 037540
start hlt ; wait for first address
lda ;
dac fad ; save in FAD
hlt ; wait for end address
lda ;
sub fad ; get length of block punch
cma ; ones complement the count
dac mwd ; save as 'minus number of words'
asm ; test if end address < first
jmp start ; jump if so
doblk add allbits ; test if num words
asp ; skip if
cla ;
sub allbits ;
dac wtb ; save in 'words this block'
cia ; twos complement block count
jms pbyte ; output word count BYTE
add mwd ;
dac mwd ;
lac fad ;
jms pword ; output block address WORD
cla ;
dac smc ;
loop lac *fad ;
jms pword ;
jms updchs ; update checksum
isz fad ; move address to next word
isz wtb ; check block finished
jmp loop ; jump if NOT, continue
lac smc ;
jms pword ; outp[ut checksum WORD
lac mwd ; are we finished the block punch?
asz ; skip if no more words to punch
jmp doblk ; punch next block
jmp start ; punch finished
;------------------------
; Punch two bytes (a WORD) from AC
;------------------------
pword bss 1 ;
rar 3 ; shift high byte to lower in AC
rar 3 ;
rar 2 ;
jms pbyte ; punch high byte
ral 3 ; get low byte to AC low byte
ral 3 ;
ral 2 ;
jms pbyte ; punch low byte
jmp *pword ;
;------------------------
; Punch low byte of AC (AC left unchanged)
;------------------------
pbyte bss 1 ;
tsf ; skip if TTYOUT free
jmp .-1 ; wait until TTYOUT is free
tpc ; punch and clear flag
jmp *pbyte ;
;------------------------
; Update checksum, new value in AC
;------------------------
updchs bss 1 ;
cll ; clear link
add smc ; add new value
lsz ; skip if no overflow
iac ; else increment checksum
dac smc ; put updated checksum back
jmp *updchs ;
;------------------------
; What were literals in original code stored here
;------------------------
fad data 0 ; first address
mwd data 0 ; minus number of words
wtb data 0 ; num words in this block
smc data 0 ; checksum
allbits data 0377 ; byte of all bits
;------------------------
; Punch block loader
;------------------------
org start+0100 ; 037540 + 0100 = 037640
pbldr lwc 0100 ;
dac fad ;
lwc 076 ;
dac wtb ;
pbloop lac *fad ;
jms pword ;
isz fad ;
isz wtb ;
jmp pbloop ;
jmp pldr ; punch leader
;------------------------
; Punch leader
;------------------------
org start+0120 ; 037540 + 0120 = 037660
pldr lwc 07 ; we want 16 bytes of leader (8 words)
dac wtb ; store leader count
cla ;
jms pword ;
isz wtb ;
jmp .-2 ;
jmp start ; wait for first address
;------------------------
; Punch end code
;------------------------
org start+0130 ; 037540 + 0130 = 037670
pend law 0377 ;
jms pbyte ;
jms pbyte ;
jms pbyte ;
jmp pldr ; punch more leader
end