sh.s: more stuff working
This commit is contained in:
Phil Budne
+120
-95
@@ -3,6 +3,8 @@
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" started by p budne 3/4/2016
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" with code from cat.s, init.s, and looking at the v1 (pdp-11) shell
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" XXX cat.s seems to write error output on fd 8
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start:
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" XXX take command line argument (script file to open), suppress prompt??
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" NOTE!!! v0 init.s doesn't set up the argv at the top of memory,
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@@ -21,30 +23,31 @@ interactive:
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newline:
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lac d1; sys write; prompt; 1 " output prompt
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newcom:
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dzm argc " clear arg count
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dzm char " clear saved char
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dzm infile " clear input redirect file name
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dzm outfile " clear output redirect file name
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dzm argv0 " clear out argv0 for chdir comparison
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dzm argv0+1
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dzm argv0+2
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lac argcptr
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dac argptr
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lac iopt " reset output pointer
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dac opt
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dac nextarg
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" reset high memory
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dzm argc " clear arg count
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lac argcptr
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dac argptr
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dzm argv0 " clear out argv0 for chdir comparison
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dzm argv0+1
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dzm argv0+2
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newarg:
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-8 " save 8 chars
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dac bcount
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dzm redirect
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lac opt " save start for print (TEMP)
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dac 8f
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dac nextarg
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jms blank " skip whitespace
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sad o12 " newline?
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jms delim " newline?
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jmp eol " yes
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sad lt " input redirect?
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jmp redirin
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@@ -56,23 +59,21 @@ redirin: " saw <
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dac redirect " flag redirect
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lac infilep
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dac opt
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dac 8f " TEMP
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jmp newchar " v1 behavior? no whitespace eater
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redirout: " saw >
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dac redirect " flag redirect
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lac outfilep
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dac opt
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dac 8f " TEMP
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" v1 behavior? no whitespace eater
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" v1 behavior? no whitespace eater!
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" fall
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newchar:
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jms getc
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sad o40 " space?
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jmp ws " yes
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sad o12
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jmp ws
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jms delim
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jmp eoname
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3: jms putc " save
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isz bcount " loop unless full
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jmp newchar
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@@ -83,20 +84,20 @@ discard:
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dac char
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sad o4
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jmp eof
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sad o12
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jms delim " end of line?
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jmp eoname
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sad o40
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jmp eoname
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jmp discard
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" here with EOF in command
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" here with EOF in command: process command?
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eof:
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sys exit " quit, for now?
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" name ended (short) with whitespace or newline
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" pad out last name to 8 with spaces
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ws:
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dac char
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dac char " save terminator
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1: lac o40
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jms putc " no: copy into argv
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isz bcount " loop until full
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@@ -104,9 +105,10 @@ ws:
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" saw end of name
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eoname:
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dac char
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lac redirect
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sza
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jmp 1f " last name was a redirect file, skip increment
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jmp 2f " last name was a redirect file, skip increment
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lac argc " increment argc
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tad d4
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@@ -115,19 +117,13 @@ eoname:
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tad d4 " advance nextarg
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dac nextarg
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1f:
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2:
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dzm redirect " clear redirect flag
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" TEMP output each name on a line:
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lac d1; sys write; gt; 1
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lac d1; sys write; 8:0; 4
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lac d1; sys write; nl; 1
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lac nextarg
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dac opt
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dac 8b " TEMP
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lac char
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sad o12
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jms delim
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jmp eol
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-maxargs
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@@ -135,41 +131,42 @@ eoname:
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sza
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jmp newarg
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" too many args, (complain?) eat rest of line
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" too many args, (complain?). for now eat rest of line
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4: jms getc
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sad o12
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jms delim
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skp
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jmp 4b
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lac d1; sys write; toomany; ltoomany
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jmp newline
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" here at end of line
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eol:
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cla " get anything?
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sad argc
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jmp newline " no, go back for another
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sad delimchar " save eol character
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lac argc " check for empty command line
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sna " get anything?
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jmp 2f " no, go back for another
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lac argv0 " check for built-in "chdir" command
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sad chdir
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" check for built-in "chdir" command
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lac argv0
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sad chdirstr
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skp
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jmp forkexec
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jmp 1f
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lac argv0+1
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sad chdir+1
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sad chdirstr+1
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skp
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jmp forkexec
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jmp 1f
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lac argv0+2
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sad chdir+2
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sad chdirstr+2
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jmp changedir
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forkexec:
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" temp just exec in place
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" sys fork
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" jmp parent
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dac pid " here in child: save parent pid for smes
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1:
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" comment these out to test "exec"
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sys fork
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jmp parent
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" here in child
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lac d2; sys close " close fd 2
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" XXX open executable BEFORE I/O redirection, so we can output error!!!!
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sys unlink; exectemp
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sys unlink; exectemp " remove temp file
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" try to link binary from "system" directory to "exectemp" file
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" sys link; system; argv0; exectemp
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@@ -180,13 +177,8 @@ forkexec:
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" jmp error
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" sys unlink; exectemp
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" jmp 1f
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"notsys: " not found in "system"
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lac d1; sys write; star; 1
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lac d1; sys write; star; 1
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lac d1; sys write; argv0; 4
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lac d1; sys write; nl; 1
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notsys: " not found in "system"
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sys open; argv0; 0 " try cwd
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spa
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jmp cmderr
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@@ -207,16 +199,15 @@ notsys: " not found in "system"
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spa
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jmp outerror
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" here to "exec" file open on fd 2, adapted from init.s:
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" here to "exec" file open on fd 2, adapted from init.s
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exec:
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law boot-1 " Get source addr
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dac 8 " set up index 8 (pre-increments)
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law bootloc-1 " Copy the code at the boot label into high memory
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law bootloc-1 " Copy "boot" code into high memory
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dac 9 " set up index 9 (pre-increments)
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1: lac 8 i
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dac 9 i
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isz bootcount
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isz bootcount " can only do this once!
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jmp 1b
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jmp bootloc " and then jump to the code
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@@ -236,39 +227,67 @@ bootcount: -bootlen " isz loop count for bootstrap copy
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inerror: " error opening input redirection
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lac infilep
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jmp error
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outerror: " error opening output redirection (stdout closed!)
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outerror: " error opening new stdout (stdout closed!)
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lac outfilep
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skp
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cmderr: " error opening command
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lac argv0p
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error: " here for error in child: filename pointer in AC
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error: " error in child: filename pointer in AC
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dac 1f " save filename to complain about
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lac d1; sys write; qmsp; 1
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lac d1; sys write; 1: 0; 4
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lac d1; sys write; nl; 1
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lac d1; sys write; qmnl; 1
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lac d2; sys close
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sys exit
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" end code from init.s
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" ================
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" chdir command: executed in shell process
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changedir:
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" XXX check if argc == 4 (no directories) and complain??
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lac argv0p
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skp
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1: lac 0f " increment argvp
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tad d4
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sad 0f
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-4 " decrement argc
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tad argc
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dac argc
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sna " done?
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jmp 2f " yes: join parent code
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sys chdir; 0:0
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sma " error?
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jmp 1b " no: look for another directory
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" chdir call failed
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lac 0b
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dac 0f
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lac d1; sys write; 0:0; 4
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lac d1; sys write; qmnl; 1
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jmp 2f " join parent code
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" here in parent, child pid in AC
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parent:
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" sys smes " hangs until child exits
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jmp newline
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" chdir command:
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changedir:
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" XXX check argc > 1!!!
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lac d1; sys write; gt; 1
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lac d1; sys write; gt; 1
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lac d1; sys write; gt; 1
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lac d1; sys write; argv0+4; 4
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" XXX loop for multiple components!!!
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jmp newline
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" https://www.bell-labs.com/usr/dmr/www/hist.html
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" The message facility was used as follows: the parent shell, after
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" creating a process to execute a command, sent a message to the new
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" process by smes; when the command terminated (assuming it did not
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" try to read any messages) the shell's blocked smes call returned an
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" error indication that the target process did not exist. Thus the
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" shell's smes became, in effect, the equivalent of wait.
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dac pid
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lac delimchar
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sad o46 " ampersand?
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jmp newcom " yes: go back without wait
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lac pid
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sys smes " hang until child exits
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2: lac delimchar
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sad o73 " semi?
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jmp newcom " yes: look for another command w/o prompt
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jmp newline " no: output prompt
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" ================
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" subroutines
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" eat spaces
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" v1 routine name:
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blank: 0
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1: jms getc
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sad o40
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@@ -276,25 +295,29 @@ blank: 0
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jmp blank i
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" give skip return if AC *NOT* a command delimiter
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" v1 routine name:
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delim: 0
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sad o12
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sad o12 " newline
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jmp delim i
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isz delim
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sad o46 " ampersand
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jmp delim i
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sad o73 " semi
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jmp delim i
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isz delim " ran the gauntlet: skip home
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jmp delim i
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" ****************************************************************
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" from cat.s
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getc: 0
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lac ipt " Load the pointer to the next word in the buffer
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lac ipt " Load pointer to next word in the buffer
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sad eipt
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jmp 1f " We've reached the end of the buffer, so read more
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jmp 1f " end of the buffer, so read more
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dac 2f " Save the pointer
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add o400000 " Flip the msb and save into ipt
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add o400000 " flip MSB, increment pointer on overflow
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dac ipt
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ral " Move the msb into the link register
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lac 2f i " Load the word from the buffer
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szl " Skip if this is the second character in the word
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lrss 9 " It's the first char, shift down the top character
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szl " Skip if second character in word
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lrss 9 " first char: shift down the top character
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and o177 " Keep the lowest 7 bits
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sna
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jmp getc+1 " Skip a NUL characters and read another one
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@@ -341,37 +364,38 @@ eipt: 0 " Pointer to end of data read in input buffer
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iipt: ibuf
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ibuf: .=.+64
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" end from cat.s
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" ****************************************************************
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" literals
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d1: 1
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d2: 2
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o4:d4: 4
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o12:nl: 012 " newline
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o12: 012 " newline
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o17: 017
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o40:sp: 040 " space
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o74:lt: 074
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o76:gt: 076
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o177: 0177 " ASCII mask
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o400000: 0400000 " Msb toggle bit
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o40: 040 " space
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o46: 046 " ampersand
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o73: 046 " semi
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o74:lt: 074 " <
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o76:gt: 076 " >
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o177: 0177 " 7-bit (ASCII) mask
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o400000: 0400000 " MSB
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hash: <#> " superuser prompt
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qmsp: <? > " " question mark, space
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" (traditional DDT error label was "dt"
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" for "dink, tab")
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qmnl: <? 012 " question mark, newline
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system:
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<sy>;<st>;<em>; 040040
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exectemp:
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<ex>;<ec>;<te><mp> " temporary link for file being exec'ed
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<ex>;<ec>;<te>;<mp> " temporary link for file being exec'ed
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chdir:
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chdirstr:
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<ch>;<di>;<r 040
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" TEMP FOR DEBUG:
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star: <*> "
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toomany: <to>;<o> ;<ma>;<ny>;< a>;<rg>;<s 012
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ltoomany=.-toomany
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" ################ variables
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prompt: <@> " v1 prompt
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@@ -379,6 +403,7 @@ pid: 0 " "other" pid
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char: 0 " white space char
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redirect: 0 " last file was a redirect (lt or gt)
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bcount: 0 " byte counter for current filename
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delimchar: 0 " character that terminated line
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iopt:argv0p: argv0 " initial value for nextarg, opt
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nextarg: 0 " next slot in argv to fill
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Reference in New Issue
Block a user