mirror of
https://github.com/DoctorWkt/unix-jun72.git
synced 2026-04-24 19:40:13 +00:00
f7108bb0eb
according to what seemed right by reading the code. Documented all of the changes in notes.txt. Mostly accepting the hand written corrections in the pdf file.
58 lines
1.7 KiB
Plaintext
58 lines
1.7 KiB
Plaintext
bic $!177,r3 / to make it teletype code and then clear
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/ bits 7-15 of r3
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3:
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mov (sp),r2 / r2 contains 8xtty number
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bit $4,rcsr(r2) / is carrier present for tty
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beq starxmt / no carrler flush
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mov r1,-(sp) / yes, place character to be output on stack
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cmp r1,$11 / is character "ht"
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bne 3f / no
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bitb $2,tty+4(r2) / is tab to space flag for tty set
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/ (bit 1 of byte 5 in "tty" buffer area)
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beq 3f / no
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mov $240,(sp) / yes, change character to space
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3:
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mov (sp)+,tcbr(r2) / place char to be output in tty output
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/ buffer
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add $tty+1,r2 / place addr of 2nd byte of "tty" buf
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jmp 1f-2(r3) / area in r2 (which is the column count) and
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/ then
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incb (r2) / normal / jmp to location determined by digits
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/ 0 and 1 of character's entry in "partab" which
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/ is now in r3
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1: rts r0 / non-printing
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br 1f / bs
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br 2f / nl (line feed)
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br 3f / tab (horizontal tab)
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br 4f / vert (vertical tab)
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br 5f / cr
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1:
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decb (r2) / col decrement column count in byte 2 of "tty"
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/ area
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bge 1f / if count >=0 return to calling routine
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clrb (r2) / col set column count = 0
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br 1f
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2:
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bit $1,r1 / is bit 0 of ASC11 char = 1 (char = lf)
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bne 2f / yes
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bitb $20,3(r2) / cr flag is bit 4 of 5th byte of "tty"
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/ area = 1
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beq 2f / no (only lf to be handled)
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movb $15,1(r2) / place "cr" in 3rd byte of "tty" area
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/ (character leftover after "lf" )
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2:
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movb (r2),r3 / place present column count in r3
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beq 1f / return to calling routine if count = 0
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clrb (r2) / col clear column count
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asr r3
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asr r3
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asr r3
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asr r3 / delay = col/16
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add $3,r3 / start to determine tout entry for tty output
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br 2f
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3:
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bitb $2,3(r2) / is bit 1 of 5th byte of "tty" area = 1
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/ (tab to space bit set)
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