1972_stuff/s1/frag18
/
/
/ routine to add the two centennial numbers
/ pointed to by r2 and r3.
/ a pointer to the result is returned in r1
/ r2 and r3 are preserved
/
/ mov ptr1,r2
/ mov ptr2,r3
/ jsr pc,add3
/ mov r1,...
/
add3: mov r0,-(sp)
mov r4,-(sp)
mov r5,-(sp)
mov r3,-(sp)
mov r2,-(sp)
/
/ allocate a new string whose length is
/ the max of the two addends.
/
mov w(r2),r0
sub a(r2),r0
mov w(r3),r4
sub a(r3),r4
cmp r0,r4
bgt 1f
mov r4,r0
1: mov r0,r4
jsr pc,allocate
mov r1,-(sp)
/
/ get everything ready
/
mov 2(sp),r1
jsr pc,rewind
mov 4(sp),r1
jsr pc,rewind
clr carry
/
/ now add them
/
2: dec r4
blt 3f
mov 2(sp),r1 /r2
jsr pc,getchar
mov r0,r5
mov 4(sp),r1 /r3
jsr pc,getchar
add r5,r0
add carry,r0
clr carry
cmp r0,$100.
blt 1f
sub $100.,r0
mov $1,carry
1:
tstb r0
bpl 1f
add $100.,r0
mov $-1,carry
1: mov (sp),r1 /r1
jsr pc,putchar
br 2b
/
/ perhaps there is an extra digit
/
3: mov carry,r0
beq 2f
mov (sp),r1 /r1
jsr pc,putchar
/
/ strip leading zeros
/
2:
jsr pc,fsfile
2: jsr pc,backspace
bes 2f
beq 2b
inc r(r1)
2: mov r(r1),w(r1)
/
/ strip leading 99's
/
jsr pc,fsfile
jsr pc,backspace
cmpb r0,$-1
bne 1f
2:
jsr pc,backspace
bes 2f
cmpb r0,$99.
beq 2b
jsr pc,getchar
2:
mov $-1,r0
jsr pc,alterchar
mov r(r1),w(r1)
/
/ restore and return
/
1:
mov (sp)+,r1
mov (sp)+,r2
mov (sp)+,r3
mov (sp)+,r5
mov (sp)+,r4
mov (sp)+,r0
rts pc
/
carry: .=.+2
/
/
/ routine to change the sign of the centennial number
/ pointed to by r1.
/ negative numbers are stored in 100's complement form with
/ -1 as the high order digit; the second digit is not 99.
/
/ mov ...,r1
/ jsr pc,chsign
/
chsign:
mov r1,-(sp)
mov r0,-(sp)
jsr pc,rewind
clr chcarry
/
1:
jsr pc,lookchar
bes 1f
negb r0
sub chcarry,r0
mov $1,chcarry
add $100.,r0
cmpb $100.,r0
bgt 2f
sub $100.,r0
clr chcarry
2:
jsr pc,alterchar
br 1b
/
1:
clr r0
sub chcarry,r0
beq 2f
jsr pc,putchar
jsr pc,fsfile
jsr pc,backspace
jsr pc,backspace
cmp r0,$99.
bne 1f
mov r(r1),w(r1)
mov $-1,r0
jsr pc,putchar
br 1f
/
2:
jsr pc,fsfile
jsr pc,backspace
bne 1f
mov r(r1),w(r1)
/
1:
mov (sp)+,r0
mov (sp)+,r1
rts pc
/
chcarry: .=.+2
/
/
/
/
/ routine to multiply the two centennial numbers
/ pointed to by r2 and r3.
/ a pointer to the result is returned in r1
/ r2 and r3 are preserved
/
/ mov ptr1,r2
/ mov ptr2,r3
/ jsr pc,mul3
/ mov r1,...
/
/ save registers and make space for temps
/
mul3:
mov r5,-(sp)
mov r3,-(sp) /arg2
mov r2,-(sp) /arg1
mov r0,-(sp)
tst -(sp) /result
tst -(sp) /arg1
tst -(sp) /arg2
tst -(sp) /carry
/
/ compute sign of result and make args positive
/
clr outsign
mov r2,r1
jsr pc,fsfile
jsr pc,backspace
bmi 2f
mov r2,4(sp) /arg1
br 1f
2:
jsr pc,length
jsr pc,allocate
mov r1,4(sp)
mov r2,r0
jsr pc,move
jsr pc,chsign
com outsign
1:
mov r3,r1
jsr pc,fsfile
jsr pc,backspace
bmi 2f
mov r3,2(sp) /arg2
br 1f
2:
mov r3,r1
jsr pc,length
jsr pc,allocate
mov r1,2(sp)
mov r3,r0
jsr pc,move
jsr pc,chsign
com outsign
1:
/
/ compute the length of the result and
/ allocate space for it
/
mov w(r2),r0
sub a(r2),r0
add w(r3),r0
sub a(r3),r0
jsr pc,allocate
jsr pc,zero
mov r1,6(sp) /result
clr offset
mov 2(sp),r1 /arg2
jsr pc,rewind
/
/ work on next digit of arg2, starting over on arg1
/
1: mov 4(sp),r1 /arg1
jsr pc,rewind
mov 2(sp),r1 /arg2
jsr pc,getchar
bes 3f
mov r0,r2
mov 6(sp),r1 /result
jsr pc,rewind
add offset,r(r1)
clr 0(sp) /carry
/
/ work on next digit of arg3
/ form the product of the two digits,
/ add to what is already there and add in old carry
/ to generate new dit and new carry.
/
2: mov 4(sp),r1 /arg1
jsr pc,getchar
bes 2f
mov r0,r3
mpy r2,r3
add (sp),r3 /carry
mov 6(sp),r1 /result
jsr pc,lookchar
add r0,r3
mov r3,r1
clr r0
dvd $100.,r0
mov r0,(sp) /carry
mov r1,r0
mov 6(sp),r1 /result
jsr pc,alterchar
br 2b
/
2:
inc offset
tst (sp) /carry
beq 1b
mov 6(sp),r1 /result
jsr pc,lookchar
add (sp),r0 /carry
jsr pc,alterchar
br 1b
/
3:
/
/ change sign of result if necessary
/
tst outsign
bpl 1f
mov 6(sp),r1 /result
jsr pc,chsign
/
/ release dregs if necessary
/
1:
cmp 2(sp),14(sp)
beq 1f
mov 2(sp),r1
jsr pc,release
1:
cmp 4(sp),12(sp)
beq 1f
mov 4(sp),r1
jsr pc,release
1:
/
/ restore registers and return
/
tst (sp)+
tst (sp)+
tst (sp)+
mov (sp)+,r1
mov (sp)+,r0
mov (sp)+,r2
mov (sp)+,r3
mov (sp)+,r5
rts pc
/
outsign: .=.+2
offset: .=.+2
k: .=.+2
kptr: .=.+2
/
ookchar
add (sp),r0 /carry
jsr pc,alterchar
br 1b
/
3:
/
/ change sign of result if necessary
/
tst outsign
bpl 1f
mov 6(sp),r1 /result
jsr pc,chsi