diff --git a/src/other/sh.s b/src/other/sh.s index e57e282..87d4f44 100644 --- a/src/other/sh.s +++ b/src/other/sh.s @@ -3,6 +3,8 @@ " started by p budne 3/4/2016 " with code from cat.s, init.s, and looking at the v1 (pdp-11) shell +" XXX cat.s seems to write error output on fd 8 + start: " XXX take command line argument (script file to open), suppress prompt?? " NOTE!!! v0 init.s doesn't set up the argv at the top of memory, @@ -21,30 +23,31 @@ interactive: newline: lac d1; sys write; prompt; 1 " output prompt newcom: - dzm argc " clear arg count dzm char " clear saved char dzm infile " clear input redirect file name dzm outfile " clear output redirect file name - dzm argv0 " clear out argv0 for chdir comparison - dzm argv0+1 - dzm argv0+2 - lac argcptr - dac argptr lac iopt " reset output pointer dac opt dac nextarg +" reset high memory + dzm argc " clear arg count + lac argcptr + dac argptr + dzm argv0 " clear out argv0 for chdir comparison + dzm argv0+1 + dzm argv0+2 + newarg: -8 " save 8 chars dac bcount dzm redirect lac opt " save start for print (TEMP) - dac 8f dac nextarg jms blank " skip whitespace - sad o12 " newline? + jms delim " newline? jmp eol " yes sad lt " input redirect? jmp redirin @@ -56,23 +59,21 @@ redirin: " saw < dac redirect " flag redirect lac infilep dac opt - dac 8f " TEMP jmp newchar " v1 behavior? no whitespace eater redirout: " saw > dac redirect " flag redirect lac outfilep dac opt - dac 8f " TEMP - " v1 behavior? no whitespace eater + " v1 behavior? no whitespace eater! " fall newchar: jms getc sad o40 " space? jmp ws " yes - sad o12 - jmp ws + jms delim + jmp eoname 3: jms putc " save isz bcount " loop unless full jmp newchar @@ -83,20 +84,20 @@ discard: dac char sad o4 jmp eof - sad o12 + jms delim " end of line? jmp eoname sad o40 jmp eoname jmp discard -" here with EOF in command +" here with EOF in command: process command? eof: sys exit " quit, for now? " name ended (short) with whitespace or newline " pad out last name to 8 with spaces ws: - dac char + dac char " save terminator 1: lac o40 jms putc " no: copy into argv isz bcount " loop until full @@ -104,9 +105,10 @@ ws: " saw end of name eoname: + dac char lac redirect sza - jmp 1f " last name was a redirect file, skip increment + jmp 2f " last name was a redirect file, skip increment lac argc " increment argc tad d4 @@ -115,19 +117,13 @@ eoname: tad d4 " advance nextarg dac nextarg -1f: +2: dzm redirect " clear redirect flag -" TEMP output each name on a line: - lac d1; sys write; gt; 1 - lac d1; sys write; 8:0; 4 - lac d1; sys write; nl; 1 - lac nextarg dac opt - dac 8b " TEMP lac char - sad o12 + jms delim jmp eol -maxargs @@ -135,41 +131,42 @@ eoname: sza jmp newarg -" too many args, (complain?) eat rest of line +" too many args, (complain?). for now eat rest of line 4: jms getc - sad o12 + jms delim skp jmp 4b + lac d1; sys write; toomany; ltoomany + jmp newline " here at end of line eol: - cla " get anything? - sad argc - jmp newline " no, go back for another + sad delimchar " save eol character + lac argc " check for empty command line + sna " get anything? + jmp 2f " no, go back for another - lac argv0 " check for built-in "chdir" command - sad chdir +" check for built-in "chdir" command + lac argv0 + sad chdirstr skp - jmp forkexec + jmp 1f lac argv0+1 - sad chdir+1 + sad chdirstr+1 skp - jmp forkexec + jmp 1f lac argv0+2 - sad chdir+2 + sad chdirstr+2 jmp changedir -forkexec: -" temp just exec in place -" sys fork -" jmp parent - - dac pid " here in child: save parent pid for smes +1: +" comment these out to test "exec" + sys fork + jmp parent +" here in child lac d2; sys close " close fd 2 - -" XXX open executable BEFORE I/O redirection, so we can output error!!!! - sys unlink; exectemp + sys unlink; exectemp " remove temp file " try to link binary from "system" directory to "exectemp" file " sys link; system; argv0; exectemp @@ -180,14 +177,9 @@ forkexec: " jmp error " sys unlink; exectemp " jmp 1f +"notsys: " not found in "system" - lac d1; sys write; star; 1 - lac d1; sys write; star; 1 - lac d1; sys write; argv0; 4 - lac d1; sys write; nl; 1 - -notsys: " not found in "system" - sys open; argv0; 0 " try cwd + sys open; argv0; 0 " try cwd spa jmp cmderr @@ -207,68 +199,95 @@ notsys: " not found in "system" spa jmp outerror - -" here to "exec" file open on fd 2, adapted from init.s: +" here to "exec" file open on fd 2, adapted from init.s exec: - law boot-1 " Get source addr - dac 8 " set up index 8 (pre-increments) - law bootloc-1 " Copy the code at the boot label into high memory - dac 9 " set up index 9 (pre-increments) + law boot-1 " Get source addr + dac 8 " set up index 8 (pre-increments) + law bootloc-1 " Copy "boot" code into high memory + dac 9 " set up index 9 (pre-increments) 1: lac 8 i dac 9 i - isz bootcount + isz bootcount " can only do this once! jmp 1b - jmp bootloc " and then jump to the code + jmp bootloc " and then jump to the code " copied up to bootloc in high memory (below argc) boot: - lac d2 " Load fd 2 (the opened executable) - lmq " Save the fd into MQ + lac d2 " Load fd 2 (the opened executable) + lmq " Save the fd into MQ sys read; userbase; userlen " read executable in - lacq " Get the fd back and close the file + lacq " Get the fd back and close the file sys close - jmp userbase " and jump to the beginning of the executable -bootlen=.-boot " length of bootstrap + jmp userbase " and jump to the beginning of the executable +bootlen=.-boot " length of bootstrap -bootcount: -bootlen " isz loop count for bootstrap copy +bootcount: -bootlen " isz loop count for bootstrap copy " error in child process: -inerror: " error opening input redirection +inerror: " error opening input redirection lac infilep jmp error -outerror: " error opening output redirection (stdout closed!) +outerror: " error opening new stdout (stdout closed!) lac outfilep skp -cmderr: " error opening command +cmderr: " error opening command lac argv0p -error: " here for error in child: filename pointer in AC - dac 1f " save filename to complain about - lac d1; sys write; qmsp; 1 +error: " error in child: filename pointer in AC + dac 1f " save filename to complain about lac d1; sys write; 1: 0; 4 - lac d1; sys write; nl; 1 + lac d1; sys write; qmnl; 1 lac d2; sys close sys exit -" end code from init.s -" ================ +" chdir command: executed in shell process +changedir: +" XXX check if argc == 4 (no directories) and complain?? + lac argv0p + skp +1: lac 0f " increment argvp + tad d4 + sad 0f + -4 " decrement argc + tad argc + dac argc + sna " done? + jmp 2f " yes: join parent code + sys chdir; 0:0 + sma " error? + jmp 1b " no: look for another directory + +" chdir call failed + lac 0b + dac 0f + lac d1; sys write; 0:0; 4 + lac d1; sys write; qmnl; 1 + jmp 2f " join parent code " here in parent, child pid in AC parent: -" sys smes " hangs until child exits - jmp newline - -" chdir command: -changedir: -" XXX check argc > 1!!! - lac d1; sys write; gt; 1 - lac d1; sys write; gt; 1 - lac d1; sys write; gt; 1 - lac d1; sys write; argv0+4; 4 -" XXX loop for multiple components!!! - jmp newline +" https://www.bell-labs.com/usr/dmr/www/hist.html +" The message facility was used as follows: the parent shell, after +" creating a process to execute a command, sent a message to the new +" process by smes; when the command terminated (assuming it did not +" try to read any messages) the shell's blocked smes call returned an +" error indication that the target process did not exist. Thus the +" shell's smes became, in effect, the equivalent of wait. + dac pid + lac delimchar + sad o46 " ampersand? + jmp newcom " yes: go back without wait + lac pid + sys smes " hang until child exits +2: lac delimchar + sad o73 " semi? + jmp newcom " yes: look for another command w/o prompt + jmp newline " no: output prompt " ================ " subroutines + +" eat spaces +" v1 routine name: blank: 0 1: jms getc sad o40 @@ -276,25 +295,29 @@ blank: 0 jmp blank i " give skip return if AC *NOT* a command delimiter +" v1 routine name: delim: 0 - sad o12 + sad o12 " newline jmp delim i - isz delim + sad o46 " ampersand + jmp delim i + sad o73 " semi + jmp delim i + isz delim " ran the gauntlet: skip home jmp delim i -" **************************************************************** " from cat.s getc: 0 - lac ipt " Load the pointer to the next word in the buffer + lac ipt " Load pointer to next word in the buffer sad eipt - jmp 1f " We've reached the end of the buffer, so read more + jmp 1f " end of the buffer, so read more dac 2f " Save the pointer - add o400000 " Flip the msb and save into ipt + add o400000 " flip MSB, increment pointer on overflow dac ipt ral " Move the msb into the link register lac 2f i " Load the word from the buffer - szl " Skip if this is the second character in the word - lrss 9 " It's the first char, shift down the top character + szl " Skip if second character in word + lrss 9 " first char: shift down the top character and o177 " Keep the lowest 7 bits sna jmp getc+1 " Skip a NUL characters and read another one @@ -341,37 +364,38 @@ eipt: 0 " Pointer to end of data read in input buffer iipt: ibuf ibuf: .=.+64 - -" end from cat.s -" **************************************************************** " literals d1: 1 d2: 2 o4:d4: 4 -o12:nl: 012 " newline +o12: 012 " newline o17: 017 -o40:sp: 040 " space -o74:lt: 074 -o76:gt: 076 -o177: 0177 " ASCII mask -o400000: 0400000 " Msb toggle bit +o40: 040 " space +o46: 046 " ampersand +o73: 046 " semi +o74:lt: 074 " < +o76:gt: 076 " > +o177: 0177 " 7-bit (ASCII) mask +o400000: 0400000 " MSB hash: <#> " superuser prompt -qmsp: " " question mark, space - " (traditional DDT error label was "dt" - " for "dink, tab") +qmnl: ;;; 040040 exectemp: - ;; " temporary link for file being exec'ed + ;;; " temporary link for file being exec'ed -chdir: +chdirstr: ;; " +toomany: ; ;;;< a>;; " v1 prompt @@ -379,6 +403,7 @@ pid: 0 " "other" pid char: 0 " white space char redirect: 0 " last file was a redirect (lt or gt) bcount: 0 " byte counter for current filename +delimchar: 0 " character that terminated line iopt:argv0p: argv0 " initial value for nextarg, opt nextarg: 0 " next slot in argv to fill