TITLE BEER - 99 Bottles of beer on the wall
;
; By Mark H. Zellers
;
; This program emits the song 99-bottles of beer on the wall
; It is a demonstration of PDP-10 assembly language
;
; This program can be run on the SIMH emulator using the TOPS-10
; Operating system.
;
; For more information, see
http://www.aracnet.com/~healyzh/pdp10emu.html
; Or consult Wikipedia for more information about the PDP-10
;
SEARCH UUOSYM
; Define some registers
; note that registers 0 and 1 are used for scratch
N==2 ; Register containing number of bottles
D==3 ; Digits to output
E==4 ; Ending (either take one down or go to the stor
e)
B==5 ; "Bottles" or "Bottle"
LC==6 ; Either D or "no "
START:: MOVEI N,^D99 ; Initialize number of bottles
MOVEI E, [ASCIZ /You take one down, pass it around, /]
LOOP:
; Convert the current count to a string
;
MOVE 0,N
IDIVI 0,^D10
JUMPE 0,ONEDIG
ROT 0,-7 ; Move high digit to first character
ROT 1,^D-14 ; Move low digit to second character
IOR 0,1 ; Merge the two characters together
ADD 0,[BYTE (7)60,60,40,0,0] ; Convert to ASCII and append a blank
JRST OUTPUT
ONEDIG: MOVE 0,1
ROT 0, -7
ADD 0,[BYTE (7)60,40,0,0,0]
OUTPUT: MOVE D,0 ; Move result into digit buffer
; Use the appropriate ending for bottles
MOVEI B,[ASCIZ/bottles/]
CAIN N,1
MOVEI B,[ASCIZ/bottle/]
;
; Now check for whether we want the digits or the word no
MOVEI LC,D ; Assume we want the digits
;
JUMPN N,PASSIT
MOVE D,[ASCIZ/No /]
MOVEI LC,[ASCIZ /no /]
MOVEI E,[ASCIZ /You go to the store and buy some more,/]
; Now output the strings
;
PASSIT:
CAIN N,^D99 ; Skip repeat on first verse
JRST SKIPRP
OUTSTR 0(LC)
OUTSTR 0(B) ; "Bottles" or "bottle"
OUTSTR [ASCIZ / of beer on the wall.
/]
SKIPRP: OUTSTR D ; Number of bottles
OUTSTR 0(B) ; "Bottles" or "Bottle"
OUTSTR [ASCIZ/ of beer on the wall, /]
OUTSTR 0(LC) ; Number of bottles or "no"
OUTSTR 0(B)
OUTSTR [ASCIZ/ of beer.
/]
OUTSTR 0(E) ; Take one down or go to store
SOJGE N,LOOP ; Decrement N and loop if N>=0
OUTSTR [ASCIZ/ 99 bottles of beer on the wall./]
EXIT
END START
