Subtract Normalized (Ser) (Se) (Sdr) (Sd) - RCA 70/46 Reference Manual

Subtract Normalized
(SER) (SE) (SDR) (SD)
General Description
Format
(RR
Short)
(RX
Short)
(RR Long)
(RX Long)
Condition Code
Interrupt Action
Floating-Point Instructions
• The operand specified by the second address (R
2
or X
2
/B
2
/D
2 )
is sub-
tracted from the operand in the floating-point register specified by the first
address (R
1 ) .
The normalized difference is loaded into the register specified
by the first address. The sign and magnitude of the difference determine
the condition code.
o
7 8 11 12 15
o
7 8 11 12 15 16 19 20
o
7 8 11 12 15
o
7 8 11 12 15 16 19 20
• 0 - result mantissa is zero.
1 - result mantissa is less than zero.
2 - result mantissa is greater than zero.
3 - result exponent overflows.
• Address error:
Addressing (RX format).
Specification.
Significance error.
Exponent overflow.
Exponent underflow.
31
31
Notes •
1.
The Subtract Normalized is the same as the Add Normalized, except
that the sign of the second operand is changed to the opposite value
before addition. A zero difference is always positive.
213