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DoctorWkt.pdp7-unix/bin/chmod
2016-03-04 13:41:16 +10:00

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010000: 237777 lac 017777 i " Have we got any arguments?
010001: 550101 sad d4
010002: 610073 jmp error " No, give an error
010003: 217777 lac 017777
010004: 350101 tad d4 " Skip past argc
010005: 040010 dac 8 " and save the ptr to the octal value at location 8
010006: 350100 tad d1 " Why only 1 here?
010007: 050053 dac name " Save the filename pointer
010010: 150111 dzm octal " Zero the octal value and
010011: 150107 dzm nchar " the number of characters
010012: 777770 -8 " Set c1 to -8 so we can increment up to zero
010013: 050110 dac c1 " and thus count the number of chars in the argument
010014: 210107 lac nchar " Get any left-over character from the last loop
010015: 150107 dzm nchar " and set nchar to empty now
010016: 740200 sza " It was already empty, so get a new word
010017: 610026 jmp 2f " Not empty, it has the second ASCII value, goto 2f
010020: 220010 lac 8 i " Read the next word with two chars in it
010021: 652000 lmq " Copy it to MQ
010022: 510105 and o177 " Trim off all but the second ASCII value
010023: 050107 dac nchar " Save it into nchar
010024: 641002 lacq " Bring it back from MQ
010025: 660511 lrss 9 " and shift down the first ASCII value
010026: 550104 sad o40 " If the character is a space
010027: 610037 jmp 3f " don't try to make it part of the octal value
010030: 350106 tad om60 " Not a space, subtract 060 i.e. '0'
010031: 652000 lmq " Move it into MQ
010032: 210111 lac octal " Load the octal value up to here
010033: 744000 cll; als 3 " Shift it left 3 bits
010034: 640703
010035: 640002 omq " OR in the digit from MQ
010036: 050111 dac octal " and save back in the octal value
010037: 450110 isz c1 " Is that the last character?
010040: 610014 jmp 1b " No, go back and get another one
010041: 237777 lac 017777 i " How many arguments left?
010042: 550102 sad d8
010043: 020016 sys exit " None, exit
010044: 350103 tad dm4 " Subtract 4 to indicate one less argument
010045: 077777 dac 017777 i " and save for next time
010046: 210053 lac name " Also move to the next filename
010047: 350101 tad d4
010050: 050053 dac name
010051: 210111 lac octal " Set AC to have the new file mode
010052: 020022 sys chmod; name:0 " and change the file's mode
010053: 000000
010054: 740100 sma
010055: 610041 jmp loop " Loop if no error
010056: 210053 lac name " We got back -1, error
010057: 050062 dac 1f " Write out the filename on stdout
010060: 210100 lac d1 " followed by the " ?\n" string
010061: 020005 sys write; 1:0; 4 " and loop back
010062: 000000
010063: 000004
010064: 210100 lac d1
010065: 020005 sys write; 1f; 2
010066: 010071
010067: 000002
010070: 610041 jmp loop
010071: 000040 040;077012 " String literal " ?\n"
010072: 077012
010073: 210100 lac d1 " Write " "\n" to stdout and exit
010074: 020005 sys write; 1b+1; 1
010075: 010072
010076: 000001
010077: 020016 sys exit
010100: 000001 d1: 1 " Numeric constants
010101: 000004 d4: 4
010102: 000010 d8: 8
010103: 777774 dm4: -4
010104: 000040 o40: 040
010105: 000177 o177: 0177
010106: 777720 om60: -060