Elliott 803 Algol 60 Compiler (reconstructed)

File: buffer.t2

For general comments see here
LineAddressObject Code LabelF1N1BF2N2CommentsCheck
1 0  ; tape2/buffer.t2
2 0  ;----------------
3 0  ; advance, buffer
4 0  ;
5 0  Advance::; 
6 0  ;
7 0  ; scratch data areas used locally
8 0  ;
9 0  =7241 
10 7241 0000000000000.shift:+0; 0/32 based on current character shift
11 7242  .currchar:; 
12 7242 0000000000000 +0; save for current character
13 7243  =7252 
14 7252  .rdrnum:; 
15 7252 0000000000000 +0; reader number (arg1*2**11)
16 7253  =7684 
17 7684  ;
18 7684  ; advance(d)
19 7684  ;
20 7684  Advance:; 
21 7684 0600016 lod arg1   ;check arg1 for limits @7684
22 7684+0116210 add N1   ;=-1
23 7685 1137006 jn .A1   ; @7685
24 7685+0136223 sub K4   ;=4
25 7686 1137007 jn .A2   ; @7686
26 7686+ .A1:; 
27 7686+0040000 o02 0   ;=1, arg1 out of range - take default
28 7687 0400016 sto arg1   ; @7687
29 7687+ .A2:; 
30 7687+0600016 lod arg1   ;shift reader number to hw posn
31 7688 1320013 sll 11   ; @7688
32 7688+0416124 sto .rdrnum   ;and save for later
33 7689 0000072600077 o00 arg1/lod RdBuff-1;load current buffer @7689
34 7690 0076225 and K32   ;=32 mask shift @7690
35 7690+ .A3:; 
36 7690+0416111 sto .shift   ;save shift
37 7691  .A4:; 
38 7691 0670523614000 cla .rdrnum/inp -2048;get next character @7691
39 7692 1057013 jz .A4   ;ignore blank @7692
40 7692+0416112 sto .currchar   ;save current char
41 7693 0136215 sub K27   ;=27 check fig shift @7693
42 7693+1157012 jz .A3   ;store zero shift
43 7694 0136223 sub K4   ;=4 check letter shift @7694
44 7694+1157021 jz .A5   ;store shift=32
45 7695 0616112 lod .currchar   ;reload char @7695
46 7695+0116111 add .shift   ;add shift
47 7696 0000072400077 o00 arg1/sto RdBuff-1;store in buffer @7696
48 7697 1016043 jmp RetClr   ;return @7697
49 7697+ ;
50 7697+ ; set shift to 32
51 7697+ ;
52 7697+ .A5:; 
53 7697+0616225 lod K32   ;=32
54 7698 1117012 jmp .A3   ;store updated shift @7698
55 7698+ ;
56 7698+0000000 o00 0   ;
57 7699  ;--------------------------------------------------------------------
58 7699  ; buffer(d, str)
59 7699  ;
60 7699  ;Buffer::
61 7699  Buffer:; 
62 7699 0600016 lod arg1   ; @7699
63 7699+0116210 add N1   ;=-1
64 7700 1137025 jn .1   ; @7700
65 7700+0136223 sub K4   ;=4
66 7701 1037027 jn .2   ; @7701
67 7701+ .1:; 
68 7701+0040000 o02 0   ;
69 7702 0400016 sto arg1   ; @7702
70 7702+0000000 o00 0   ;
71 7703  .2:; 
72 7703 0000076600000 o00 arg2/lod 0;load string address @7703
73 7704 1220036 srl 30   ;shift down into AR @7704
74 7704+0076212 and K63   ;=63 mask first char
75 7705 1157042 jz .7   ;not valid char! @7705
76 7705+0416112 sto .currchar   ;store first char
77 7706 0076225 and K32   ;mask sign @7706
78 7706+0176112 bus .currchar   ;subtract sign from char
79 7707 0136215 sub K27   ;=27 figure shift @7707
80 7707+1137036 jn .4   ;ok
81 7708 0000072600077 o00 arg1/lod RdBuff-1;load current buffer char @7708
82 7709 0136112 sub .currchar   ;compare with char @7709
83 7709+1320001 sll 1   ;shift shift bit out
84 7710 1017040 jmp .5   ;set return @7710
85 7710+ ;
86 7710+ .4:; 
87 7710+0616112 lod .currchar   ;get char
88 7711 0000072120077 o00 arg1/sub RdBuff-1;compare with buffer @7711
89 7712  .5:; 
90 7712 0076212 and K63   ;=63 @7712
91 7712+1157041 jz .6   ;if zero, set false
92 7713 0616227 lod Signbit   ;=04000000000000 set true @7713
93 7713+ .6:; 
94 7713+0116227 add Signbit   ;complement value
95 7714 1016043 jmp RetClr   ;and return it @7714
96 7714+ ;
97 7714+ .7:; 
98 7714+0616577 lod Msg18   ;'BUFFER ERROR'
99 7715 1016165 jmp outerror0   ; @7715
100 7715+ ;
101 7715+0000000 o00 0   ;
102 7716  ;--------------------------------------------------------------------

Page created by Bill Purvis, last updated: January 09 2004