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Language Assembler (DEC PDP-11)
| Date: | 05/13/10 |
| Author: | Kuzmich S. |
| URL: | n/a |
| Comments: | 2 |
| Info: | http://www.cse.iitd.ernet.in/~sak/courses/cdp/cards/PDP-11.txt |
| Score: |  (3.11 in 19 votes) |
. = 1000
ostat = 0177564
odata = 0177566
istat = 0177560
idata = 0177562
start:
mov #1000,sp
jsr pc, newline
bottles:
clr r1
clr r2
add #143,r1
add #142,r2
bottles_loop:
mov r2, -(sp)
mov r1, -(sp)
mov r1, -(sp)
mov #s3, -(sp)
jsr pc, printf
add #2*4, sp
tst r2
beq no_more_bottles
dec r1
dec r2
br bottles_loop
no_more_bottles:
mov #s4, -(sp)
jsr pc, printf
add #2, sp
end:
jsr pc, newline
halt
; ===== printf =====
; int printf (const char *format, ...);
printf:
mov r5, -(sp)
mov sp, r5
add #4, r5
mov r4, -(sp)
mov r3, -(sp)
mov r2, -(sp)
mov r1, -(sp)
clr r1 ; charcount
mov (r5)+, r4 ; *format -> r4
printf_while:
movb (r4)+, r3 ; format++ -> r3
cmpb #0, r3
beq printf_end ; while char != EOF
cmpb r3, #'\
beq printf_slash
cmpb r3, #'%
beq printf_percent
br printf_normal_print
printf_slash:
movb (r4)+, r3
cmpb r3, #'n
beq printf_slash_n
mov #'\ , r3
br printf_normal_print
printf_percent:
movb (r4)+, r3 ; format++ -> r3
mov (r5)+, r2 ; arg++ -> r2
cmpb r3, #'d
beq printf_percent_d
cmpb r3,#'o
beq printf_percent_o
cmpb r3,#'c
beq printf_percent_c
cmpb r3,#'s
beq printf_percent_s
mov #'n , r3
br printf_normal_print
printf_slash_n:
inc r1
jsr pc, newline
br printf_while
printf_percent_d:
mov r2, -(sp)
jsr pc, putdec
add #2, sp
add r0, r1
br printf_while
printf_percent_o:
mov r2, -(sp)
jsr pc, putoct
add #2, sp
add r0, r1
br printf_while
printf_percent_c:
mov r2, -(sp)
jsr pc, putch
add #2, sp
inc r1
br printf_while
printf_percent_s:
mov r2, -(sp)
jsr pc, puts
add #2, sp
add r0, r1
br printf_while
printf_normal_print:
mov r3, -(sp)
jsr pc, putch
add #2, sp
inc r1
br printf_while
printf_end:
mov r1, r0 ; return count of printed symbols
mov (sp)+, r1
mov (sp)+, r2
mov (sp)+, r3
mov (sp)+, r4
mov (sp)+, r5
rts pc
; ===== newline =====
; void putch ('/n')
newline:
tstb @#ostat
bpl newline
mov #12, @#odata ;
rts pc
; end
; ===== putch =====
; void putch (char a);
putch:
mov r5, -(sp)
mov sp, r5
add #4, r5
putch_loop:
tstb @#ostat
bpl putch_loop
mov (r5), @#odata
mov (sp)+, r5
rts pc
; end
; ===== putdec =====
; int putdec (int n);
putdec:
mov r5, -(sp)
mov sp, r5
add #4, r5
mov r4, -(sp)
mov r3, -(sp)
mov r2, -(sp)
mov r1, -(sp)
mov (r5), r5 ; n -> r5
clr r1 ; charcount
cmp #0, r5
ble putdec_pre_loop
putdec_if_negative:
mov #'-, -(sp)
jsr pc, putch ; putch ('-')
add #2, sp
inc r1
neg r5
putdec_pre_loop:
mov #0, r2 ; numcount
putdec_loop: ; do {
clr r4
div #10., r4 ; r4 = n / 10.
; r5 = n % 10.
add #'0, r5
mov r5, -(sp)
inc r2
mov r4, r5
cmp #0, r4 ; }
bne putdec_loop ; while (n)
putdec_loop2: ; do {
jsr pc, putch
add #2, sp
inc r1
dec r2
cmp #0, r2 ; }
bne putdec_loop2 ; while (numcount)
putdec_end:
mov r1, r0 ; return charcount
mov (sp)+, r1
mov (sp)+, r2
mov (sp)+, r3
mov (sp)+, r4
mov (sp)+, r5
rts pc
; end
; ===== putoct =====
; int putoct (int n)
putoct:
mov r5, -(sp)
mov sp, r5
add #4, r5
mov r4, -(sp)
mov r3, -(sp)
mov r2, -(sp)
mov r1, -(sp)
mov (r5), r5 ; n -> r5
clr r1 ; charcount
cmp #0, r5
ble putoct_pre_loop
putoct_if_negative:
mov #'-, -(sp)
jsr pc, putch ; putch ('-')
add #2, sp
inc r1
neg r5
putoct_pre_loop:
mov #0, r2 ; numcount
mov #7, r3
com r3
putoct_loop: ; do {
mov r5, r4
bic r3, r4
add #'0, r4
mov r4, -(sp)
inc r2
asr r5
asr r5
asr r5
cmp #0, r5 ; }
bne putoct_loop ; while (n)
putoct_loop2: ; do {
jsr pc, putch ; putch ()
add #2, sp
inc r1 ; charcount++
dec r2
cmp #0, r2 ; }
bne putoct_loop2 ; while (numcount)
putoct_end:
mov r1, r0 ; return charcount
mov (sp)+, r1
mov (sp)+, r2
mov (sp)+, r3
mov (sp)+, r4
mov (sp)+, r5
rts pc
; end
; ===== puts =====
; int puts (char *a)
puts:
mov r5, -(sp)
mov sp, r5
add #4, r5
mov r4, -(sp)
mov (r5), r5 ; *a -> r5
clr r4 ; charcount === i
puts_loop: ; while a[i] != EOF {
cmpb (r5), #0
beq puts_end
movb (r5)+, -(sp)
jsr pc, putch ; putch (a[i])
add #2, sp
inc r4 ; charcount++
br puts_loop ; }
puts_end:
mov r4, r0 ; return charcount
mov (sp)+, r4
mov (sp)+, r5
rts pc
s3:
.ASCIZ "%d bottles of beer on the wall, %d bottles of beer.\nTake one down and pass it around, %d
bottles of beer on the wall.\n\n"
s4:
.ASCIZ "No more bottles of beer on the wall, no more bottles of beer. \nGo to the store and buy
some more, 99 bottles of beer on the wall.\n"
.end
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