DATA 620/i SYSTEM REFERENCE MANUAL . - Al Kossow's Bitsavers

The contents of the effective memory location are subtracted from
the A register and the difference is placed in the A register.
After execution, if (A) ~215 (217) or < _2 15 (-2 17 ), the overflow
indicator (OF) is set.
Indexing: Yes
Indirect Addressing: Yes
Registers Altered: A, OF
Multiply (optional)
17 16 15 14 13 12 11 10 9 8
1-'-!
L_..L
16 M
I la-bit I
option
7 6
Timing: 10 cycles
(16 bits)
11 cycles
(18 bits)
5 4 3 210
The contents of the B register are multiplied by the contents of
the effective memory location. The original contents of the A
register are added to the final product. The product is placed
in the A and B registers, with the most-significant half of the
product in the A register and the least-significant half in the
B register. The sign of the product is contained in the sign
position of the A register. The sign position of the B register
is reset to zero.
The algorithm is in the form R . B + A.
Indexing: Yes
Indirect Addressing: Yes
Registers Altered: A, B, OF
A
Divide (optional)
Timing: 10-14 cycles
(16 bits)
11-15 cycles
(18 bits)
17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
r-r-! 17 M A
L _.L _..L._____----IL--__----IL--________........
IIS-bitl
option
3-11