HTTP Server written in EDSAC assembly

HttpServerInEDSAC.eds

[This is a minimal HTTP server written in EDSAC assembly.
It uses initial orders 1
The program itself starts on line 31 to align instructions with their resident memory addresses
It will run in the great EDSAC simulator found at 
http://nhiro.org/learn_language/repos/EDSAC-on-browser/index.html]

























T333S
E50S [GOTO main program, load lookup table]
PS [NEEDLE_CHAR and lastchar and output prep]
PS [HAYSTACK_CHAR]
U900S [input buffer update location]
P50S [lookup table location]
P1S [2 for incrementing ]
PS [input characters stored here]
PL [1 for incrementing]
P13L [g]
P1L [e]
P2L [t]
P10S [ ]
A900S [initial input buffer read location]
A400S [initial lookup table read location]
P9S [lookup table delimiter for separating (cr)]
U2S [for subroutines]
U400S [initial lookup table write location]
P12S [lf]
A48S[load lookup table][get lookup table loc]
T54S[write write instruction]
I38S[read input]
A38S[get input into A]
ZS[U400?S write A(input) to memory]
S46S[compare to delimiter cr/@]
G69S[not delimiter. go to increment.]
TS
A46S
S38S
G69S[not delimiter. go to increment.]
A38S[is delimiter.  compare against last char]
S33S
G69S[not repeated. go to increment.]
TS
A33S
S38S
G69S[not repeated. go to increment.]
E76S[repeated.  goto read 404.]
TS[increment, clear A first.]
A54S[load current pointer]
A37S[+2/1]
T54S[save incremented pointer]
A38S[store last char]
T33S[store last char]
E52S[loop to read next char]
A54S[read 404][load current pointer]
A37S[+2/1]
T81S[save incremented write pointer ]
I38S[read input]
A38S[get input into A]
ZS[U400?S write A(input) to memory]
S46S[compare to delimiter cr/@]
G89S[not delimiter. go to increment.]
TS
A46S
S38S
G89S[not delimiter. go to increment.]
E289S[is delimiter, go to print startup message]
TS [increment][clear]
A81S[load pointer]
E77S[loop back to increment code]
TS [called on bad request][clear]
A46S [load eof input delim (cr)]
T900S [write it]
E156S[proceed to lookup table.  should end up in 404]
PS
PS
PS
PS
ZS [read request.  should be at 100]
I38S[read a character]
A38S[put character in A]
S40S[subtract E]
G92S [if it's not, report error]
TS[clear a]
A40S[put E in A]
S38S[subtract character]
G92S [report error if <0]
I38S[read a character]
A38S[put character in A]
S41S[subtract E]
G92S [if it's not, report error]
TS[clear a]
A41S[put E in A]
S38S[subtract character]
G92S [report error if <0]
I38S[read a character]
A38S[put character in A]
S42S[subtract T]
G92S [if it's not, report error]
TS[clear a]
A42S[put T in A]
S38S[subtract character]
G92S [report error if <0]
I38S[read a character]
A38S[put character in A]
S43S[subtract !]
G92S [if it's not, report error]
TS[clear a]
A43S[put ! in A]
S38S[subtract character]
G92S [report error if <0]
A35S [read initial input pointer]
T137S [Initialize input pointer]
I38S [ read char into 38 ]
A38S
ZS [input pointer, UbufS]
S43S [subtract space]
G145S [jump ahead to increment section because it's not a space]
TS [clear A]
A43S [add space]
S38S [subtract input]
G145S [jump ahead to increment section because it's not a space]
E150S [ it's a space, break out of loop ]
TS [inputpointer++: clear a]
A137S [load input pointer]
A37S [+2]
T137S [save new input pointer]
E135S [loop back to get new input char]
TS [---add delimiter cr to mark end of input---]
A137S [load input pointer]
T154S [save new input pointer for delim]
A46S [load cr delimiter]
ZS [save delimiter at end of input UbufS]
TS[clear]
A45S [read initial lookup pointer]
T162S [initialize lookup pointer]
A44S [--search lookup table--][reset input pointer]
T160S [initialize input pointer]
ZS [compare-chars][input read pointer, AbufS]
T33S [save the char to 33]
ZS [lookup read pointer,AbufS.  need to shift.]
U34S [save the char to 34 (haystack)]
S33S [compare lookup against input]
G186S[jump to skip-to-next]
TS
A33S
S34S
G186S[jump to skip-to-next]
TS[they are equal, check for end delim]
A33S
S46S [ compare against cr]
G178S[jump to next-char]
TS
A46S
S33S [ compare against cr]
G179S[jump to next-char]
E203S[jump to print response call]
TS [next-char][clear pointer]
A160S [load pointer]
A37S [+2]
T160S [save pointer]
A162S [load pointer]
A37S [+2]
T162S [save pointer]
E160S [ jump to compare-chars]
TS [clear A] [skip-to-next]
TS [noop, this was a pause before]
A189S [save calling address]
G210S [call skip-over-next-delim]
A191S [save calling address]
G210S [call skip-over-next-delim]
A162S [see if we are at the end of the lookup table by checking for delimiter][first we need to get the lookup pointer]
T195S [save lookup pointer to next instruction]
ZS [lookup pointer A?S, read current lookup char into a]
U34S[save to haystack]
S46S[compare against delim]
G206S[goto not delim]
TS
A46S
S34S
G206S[goto not delim]
A203S[at delim, print 404]
G231S[print response]
E100S[read next request]
TS[not delim.  clear a, then]
E158S [look at next entry in lookup table]
ZS 
ZS 
A47S[subroutine skip-over-next-delim.  wheeler jump]
T225S[subroutine return order]
A162S [copy current lookup read pointer]
T214S
ZS [lookup read pointer AbufS,copied from 162 ]
U34S[save to haystack]
S46S[compare against delim]
G226S[goto advance-char]
TS
A46S
S34S
G226S[goto advance-char]
A214S [we are at delim.  set 162(lookup read pointer) to 1+current and return][load pointer]
A37S[+2]
T162S
ZS [wheeler jump return]
TS[advance-char][clear pointer]
A214S [load pointer]
A37S[+2]
T214S [save pointer]
E214S [loop back]
A47S[subroutine read headers and print current lookup pointer. wheeler jump]
T277S[subroutine return order]
TS[was stop for debugging]
TS[clear out last char at 33]
T33S
I38S[get next char]
A38S[compare it against CR]
S46S
G245S [not cr, proceed]
TS
A46S
S38S
G245S [not cr,proceed]
E236S[is cr,ignore it in headers, loop back to get next char]
TS[proceed, compare this and last char against nl]
A38S
S49S
G261S [not nl]
TS
A49S
S38S
G261S [not nl]
A38S
S33S
G261S [not nl]
TS
A33S
S38S
G261S [not nl]
E266S [both are newlines.  Proceed to output section of subroutine]
TS[not nl]
A38S[save cur as last]
T33S
E236S[loop back to read next char]
ZS
A162S [copy current lookup read pointer.  Assume it's on a delim at this time, so advance.][this was at 233]
A37S [advance]
T269S [save it to next instruction]
ZS [lookup read pointer AbufS,copied from 162]
U34S[save to haystack]
S46S[compare against delim]
G278S[goto print-char]
TS
A46S
S34S
G278S[goto print-char]
ZS [wheeler jump return][we are at delim.  return]
TS[print-char][clear pointer]
A34S[load char to print]
L1024S[shift to print it]
T33S[write shifted char to NEEDLE]
O33S[print it]
A269S [load pointer]
A37S[+2]
T269S [save pointer]
E269S [loop back to read the next one]
ZS
O333S[end of startup message]
TS[print startup message]
O297S[start of startup message]
A290S
A37S[+1/2]
U290S[set incremented output location]
S288S
G289S[loop back if not at end]
E100S[jump up to read first request]
PS
RS
ES
SS
SS
!S
RS
US
NS
!S
TS
OS
!S
SS
US
BS
MS
IS
TS
!S
RS
ES
QS
US
ES
SS
TS
!S
OS
NS
!S
TS
AS
PS
ES
&S
/@
*HTTP#/1,1!200!*OK&
&
HELLO!FROM!EDSAC&
TRY!REQUESTING!THESE!OTHER!PAGES&
#/*WILKES&
#/*WHEELER&
@
/WILKES@
*HTTP#/1,1!200!*OK&
&
MAURICE!WILKES!LED!THE!TEAM!RESPONSIBLE!&
FOR!THE!DESIGN!AND!CONSTRUCTION!OF!EDSAC&
@
/WHEELER@
*HTTP#/1,1!200!*OK&
&
DAVID!WHEELER!CREATED!THE!INITIAL!ORDERS!&
WHICH!ALLOWED!A!PROGRAM!TO!BE!LOADED!INTO!&
MEMORY!FROM!PAPER!TAPE&
@
@
*HTTP#/1,1!404!*NOT!FOUND&
&
PAGE!NOT!FOUND&
@
GET!/!HTTP/1.0@&@&
GET!/WILKES!HTTP/1.0@&@&
GET!/WHEELER!HTTP/1.0@&@&
GET!/NONEXISTENTFILE!HTTP/1.0@&@&