GE DATANET-30 Programming Reference Manual page 69

DETAILED DESCRIPTION
The following descriptions of the hardware aspects of memory addressing are given for use
when debugging programs. The General Assembly Program automatically assigns proper
addressing for each instruction.
Program Bank Addressing
Program bank addressing can only address locations in the common data bank or another loca-
tion in the same program bank. The addresses within 1024 memory locations of the base loca-
tion of the program bank in which the instruction is located may be directly addressed by an
instruction within the program bank.
The eight 1024-word program banks for an 8192-word memory are listed in the table below:
Program Bank
1
2
3
4
5
6
7
8
Start
Decimal
0000
1024
2048
3072
4096
5120
6144
7168
Octal
0000
2000
4000
6000
10000
12000
14000
16000
Memory Locations
l
End
Decimal
Octal
to
1023 1777
to
2047 3777
to
3071 5777
to
4095 7777
to
5119 11777
to
6143 13777
to
7167 15777
to
8191 17777
Each program bank has upper and lower limits for direct addressing. When it is necessary
to go from one program bank to another, indirect addressing is used. When approaching the
upper limit of a program bank,. some caution is necessary regarding the type of instruction
placed in the last location of the program bank. Upon the execution of the last instruction in
a program bank, the P-counter contains the address of the first instruction in the next program
bank.
If
a branch instruction is in the last location, the program will branch to the corresponding
address in the next program bank.
There are two ways to change from one program bank to another:
1. The P-counter counts up past the program bank boundary.
2. A branch instruction is given in the indirect mode.
[ID&lf
&~~lf
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~@------------
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