Stack Operations During Recursive Calls - HP 3000 III Series Manual

Machine Instructions and Stack Operations
CALL, AND FIRST TEST FOR ZERO
After After
After
After After
ZERO Instruction
lDI4 PCAl26 lOAD 0-4 CMPIO
f-
Data Of -
I-
Previous _
Procedure
S-+
0
0 0
0 0
S~
4 4 4 4
X
133
STA
S,O ---+
~O
0-+
S,O ---+
s-+
4
0 ® ®
® ®
FIRST RECURSIVE CALL
After
After
After After
ZERO lOAD 0-4 SUBI1 PCAl26
AFTER LAST
RECURSIVE CALL
0 0 0 0
{and LOAD 0-41
4
4 4 4
+
0
I
4
0---+
04 0-.
I
I
s---+
0
0
0 0
I
s---+
4
S---+
3
3
\.
.....
X
•
125
('
0
STA I 3
S,O ---+
6
j
X
CD
®
®
CD
I
125
\. ....
STA
6
..
SECOND RECURSIVE CALL
r'
0
After After After After
I
2
ZERO lOAD 0-4
SUBI1 PCAl26
I X
I 125
0 0 0 0
\.
STA
.....
4 4
4
4
..
6
r' 0
I
1
I
X
I
125
0
0 0 0
\.
.....
STA
3. 3 3
3
• 6
X
X X X
r'
0
I
125 125 125 125
I
0
STA
STA
STA STA
I
X
0---+
6
04
6
04
6 6
I
125
S---+
0 0 0
0 \.
....
STA
S---+
3
S4
2
2
O----j
6
X
S.-+
0
125
STA
®
S,O-+
6
0)
® CD
®
Figure 4-20. Stack Operations During Recursive calls
4-47