RCA 70/46 User Manual

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00
Priority No.
26
27
28
29
30
Condition
Exponent Overflow
Divide Error
Significance Error
Exponent Underflow
Decimal Overflow
Table 9. Interrupt Conditions (Cont'd)
Flag Bit
2
25
2
26
227
2
28
2
29
Explanation
The exponent overflow interrupt occurs when the result exponent of floating-point
addition,
subtraction, multiplication, or division is greater than 127. The operation
is terminated.
The divide error interrupt occurs when any of the following occur:
1. A
quotient exceeds the general register size in fixed-point division, including
division by zero. The division is suppressed.
2. The result of a Convert To Binary instruction exceeds one word. The conversion
is completed by ignoring information which is outside the general register size.
3. A
quotient exceeds the specified data field size in decimal divide. The division is
suppressed.
4. Floating-point division is attempted with a divisor whose mantissa is zero. The
operation is suppressed.
This interrupt occurs when the result mantissa of a floating-point add or subtract
instruction is zero. If the interrupt is permitted (by the program mask and the
interrupt mask) the operation is completed, the exponent is unaltered, and the
interrupt is taken. If the interrupt is inhibited by the program mask, the interrupt
condition is cancelled and the operation is completed by setting the result to true zero
(zero sign, zero exponent and zero mantissa). If the interrupt is permitted by the
program mask but inhibited by the interrupt mask, the interrupt remains pending
and the operation is completed by setting the result to true zero (zero sign, zero
exponent and zero mantissa).
This interrupt occurs when the result exponent of a floating-point addition, subtrac-
tion, multiplication, or division is less than zero. The operation is completed by
making the result true zero (zero sign, zero exponent, and zero mantissa). If the
interrupt is inhibited by the program mask, the interrupt condition is cancelled. If
the interrupt is permitted by the program mask, but inhibited by the interrupt mask,
the interrupt remains pending.
This interrupt occurs when the result field is too small to contain the result of a
decimal operation.
The operation is completed by ignoring the overflow data. If the
interrupt is inhibited by the program mask, the interrupt condition is cancelled. If
the interrupt is permitted by the program mask, but inhibited by the interrupt mask,
the interrupt remains pending.
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RCA 70/46 Specifications

General

Brand	RCA
Model	70/46
Category	Computer Hardware
Language	English