V2/cmd/dc4.s
.globl getchar
.globl stats
.globl lookchar
.globl fsfile
.globl seekchar
.globl backspace
.globl putchar
.globl alterchar
.globl move
.globl rewind
.globl create
.globl zero
.globl allocate
.globl release
.globl collect
.globl getword, putword
.globl length, position
.globl w, r, a, l
.globl error
/
testing = 0
/
/
/ routine to return the length of a string
/
/ mov ...,r1
/ jsr pc,length
/ mov r0,...
/
length:
mov w(r1),r0
sub a(r1),r0
rts pc
/
/
/ routine to return the read pointer position
/
/ mov ...,r1
/ jsr pc,position
/ mov r0,...
/
position:
mov r(r1),r0
sub a(r1),r0
rts pc
/
/
/
/
/ routine to get a word from the string
/ mov ...,r1
/ jsr pc,getword
/ mov r0,...
/
getword:
jsr pc,getchar
bes noch
movb r0,nchar
jsr pc,getchar
bec 2f
dec r(r1)
br noch
2: movb r0,nchar+1
mov nchar,r0
tst r0 /tst clears c-bit
rts pc
/
/
/ routine to put a word onto the string
/ mov ...,r1
/ mov ...,r0
/ jsr pc,putword
/
putword:
jsr pc,putchar
swab r0
jsr pc,putchar
swab r0
rts pc
/
nchar: .=.+2
/
/
/
/ routine to read next character from string
/ pointed to by r1; character returned in r0
/ c-bit set if character not available (end of file)
/ r1 is preserved
/
/ mov ...,r1
/ jsr pc,getchar
/ movb r0,...
/
getchar:
jsr pc,lookchar
bec 2f
rts pc
2: inc r(r1)
tst r0 /tst clears c-bit
rts pc
/
noch: clr r0
sec
rts pc
/
/ routine to look at next character from string
/ pointed to by r1; character returned in r0
/ c-bit set if character not available (end of file)
/ r1 is preserved
/
/ mov ...,r1
/ jsr pc,lookchar
/ movb r0,...
/
lookchar:
.if testing
jsr pc,plausible
inc stats+6.
.endif
cmp w(r1),r(r1)
blos noch
movb *r(r1),r0
clc
rts pc
/
plausible:
cmp r1,$headers
bhis 9f; 4; 9:
cmp r1,$headend
blo 9f; 4; 9:
rts pc
/
/
/
/ routine to move the read pointer of a string to a
/ specified point. If the string is not long enough,
/ the string is extended
/
/ mov position,r0
/ mov ...,r1
/ jsr pc,seekchar
/
seekchar:
mov r1,-(sp)
mov r0,-(sp)
.if testing
jsr pc,plausible
inc stats+10.
.endif
1:
mov (sp),r0
add a(r1),r0
cmp r0,l(r1)
bhi 3f
mov r0,r(r1)
cmp r0,w(r1)
blo 1f
mov r0,w(r1)
br 1f
3:
mov (sp),r0
jsr pc,allocate
mov 2(sp),r0
jsr pc,move
jsr pc,swap
jsr pc,release
mov 2(sp),r1
br 1b
1:
mov (sp)+,r0
mov (sp)+,r1
rts pc
/
/
/ routine to move read pointer of string to end of string
/
/ mov ...,r1
/ jsr pc,fsfile
/
fsfile:
.if testing
jsr pc,plausible
inc stats+10.
.endif
mov w(r1),r(r1)
rts pc
/
/
/ routine to read a string backwards
/ the read pointer is decremented before reading
/
/ mov ...,r1
/ jsr pc,backspace
/ mov r0,...
/
backspace:
.if testing
jsr pc,plausible
inc stats+6.
.endif
cmp a(r1),r(r1)
bhis noch
dec r(r1)
movb *r(r1),r0
clc
rts pc
/
/
/
/
/ routine to put a character into the string
/ pointed to by r1; character in r0
/ r0 and r1 are preserved.
/
/ movb ch,r0
/ mov ...,r1
/ jsr pc,putchar
/
putchar:
mov r1,-(sp)
mov r0,-(sp)
.if testing
jsr pc,plausible
inc stats+8.
.endif
1: cmp w(r1),l(r1)
blt 3f
mov w(r1),r0
inc r0
sub a(r1),r0 /W-A+1
jsr pc,allocate
mov 2(sp),r0 /r1
jsr pc,move
jsr pc,swap
jsr pc,release
mov 2(sp),r1 /r1
cmp w(r1),l(r1)
blt 3f
4
/
3: movb (sp),*w(r1)
inc w(r1)
mov (sp)+,r0
tst (sp)+
rts pc
/
/
swap:
mov w(r1),-(sp)
mov w(r0),w(r1)
mov (sp),w(r0)
mov r(r1),(sp)
mov r(r0),r(r1)
mov (sp),r(r0)
mov a(r1),(sp)
mov a(r0),a(r1)
mov (sp),a(r0)
mov l(r1),(sp)
mov l(r0),l(r1)
mov (sp)+,l(r0)
rts pc
/
/
/ routine to alter a character in the string
/ pointed to by r1; character in r0
/ r0 and r1 are preserved.
/
/ movb ch,r0
/ mov ...,r1
/ jsr pc,alterchar
/
alterchar:
mov r1,-(sp)
mov r0,-(sp)
.if testing
jsr pc,preposterous
inc stats+8.
.endif
1: cmp r(r1),l(r1)
blt 3f
mov l(r1),r0
inc r0
sub a(r1),r0 /W-A+1
jsr pc,allocate
mov 2(sp),r0 /r1
jsr pc,move
jsr pc,swap
jsr pc,release
mov 2(sp),r1 /r1
cmp r(r1),l(r1)
blt 3f
4
/
3: movb (sp),*r(r1)
inc r(r1)
cmp r(r1),w(r1)
ble 1f
mov r(r1),w(r1)
1:
mov (sp)+,r0
tst (sp)+
rts pc
/
/
/ routine to move the contents of one string
/ to another.
/
/ mov source,r0
/ mov dest,r1
/ jsr pc,move
/
/ on return, r1 points to the new string and should
/ be saved. r0 is preserved.
/
move:
mov r3,-(sp)
mov r2,-(sp)
mov r1,-(sp)
mov r0,-(sp)
mov w(r0),r2
sub a(r0),r2 /W-A
mov l(r1),r3
sub a(r1),r3 /L-A
cmp r2,r3
ble 1f
mov r2,r0
jsr pc,allocate
mov 2(sp),r0 /r1
jsr pc,swap
jsr pc,release
mov r0,r1
mov 0(sp),r0 /r0
/
1: mov a(r0),(r0)
mov a(r1),(r1)
1: dec r2
blt 1f
movb *(r0),*(r1)
inc (r0)
inc (r1)
br 1b
/
/ fix up read ptr of new string
/
1: mov r(r0),r2
sub a(r0),r2
add a(r1),r2
mov r2,r(r1)
/
/ restore and return
/
mov (sp)+,r0
mov (sp)+,r1
mov (sp)+,r2
mov (sp)+,r3
rts pc
/
/
/ routine to rewind read pointer of string
/ pointed to by r1
/
/ mov ...,r1
/ jsr pc,rewind
/
rewind:
.if testing
jsr pc,plausible
inc stats+10.
.endif
mov a(r1),r(r1)
rts pc
/
/ routine to rewind write pointer of string
/ pointed to by r1
/
/ mov ...,r1
/ jsr pc,create
/
create:
.if testing
jsr pc,plausible
inc stats+10.
.endif
mov a(r1),w(r1)
mov a(r1),r(r1)
rts pc
/
/
/ routine to zero a string
/
/ mov ...,r1
/ jsr pc,zero
/
zero:
mov r0,-(sp)
.if testing
jsr pc,preposterous
.endif
mov a(r1),r0
1: cmp r0,l(r1)
bhis 1f
clrb (r0)+
br 1b
1: mov (sp)+,r0
rts pc
/
/