acteristic is less than zero. The characteristic and
fraction are made zero, and a program interruption
occurs if the corresponding mask bit is one. Underflow
is not signaled when an operand's characteristics be
come less than zero during prenormalization, and the
correct characteristic and fraction value are used in
the multiplication.
When all 14 result fraction digits are zero, the prod
uct sign and characteristic are made zero, yielding a
true zero result without exponent underflow and ex
ponent overflow causing a program interruption. The
program interruption for lost significance is never
taken for multiplication.Condit'ion Code: The code remains unchanged. Program Interruptions: Operation (if floating-point feature is not in-
stalled)
Addressing ( MD and ME only)
Specification
Exponent overflow
Exponent underflow
Programming Note
Interchanging the two operands in a floating-point
multiplication does not affect the value of the product.
Divide
DER RR. (Short Operands)
30
78 11 12 15
DE RX (Short Operands)I 70 Rl I X
2I B2 0 7 8 11 12 1516 1920 31
DDR RR (Long Operands)I 20 Rl I R2 0 78 11 12 15
DDRX (Long Operands) I 60 Rl I X
2I B2 0 7 8 11 12 1516 1920 31
48
The dividend (the first operand) is divided by the
divisor (the second operand) and replaced by the
quotient. No remainder is preserved.
In short-precision, the low-order halves of the float
ing-point register are ignored and remain unchanged.
A floating-point division consists of a characteristic
subtraction and a fraction division. The difference be
tween thc dividend and divisor characteristics plus
64 is used as an intermediate quotient characteristic.
The sign of the quotient is determined by the rules of
algebra.
The quotient fraction is normalized by prenormaliz
ing the operands. Postnormalizing the intermediate
quotient is never necessary, but a right-shift may be
called for. The intermediate-quotient characteristic is
adjusted for the shifts. All dividend fraction digits
participate in forming the quotient, even if the normal
ized dividend fraction is larger than the normalized
divisor fraction. The quotient fraction is truncated to
the desired number of digits.
A program interruption for exponent overflow oc
curs when the final-quotient characteristic exceeds 127.
The operation is terminated.
A program interruption for exponent underflow oc
curs if the final-quotient characteristic is less than
zero. The characteristic, sign, and fraction are made
zero, and the interruption occurs if the corresponding
mask bit is one. Underflow is not signaled for the
intermediate quotient or for the operand character
istics during prenormalization.
When division by a divisor with zero fraction is at
tempted, the opcration is suppressed. The dividend
remains unchanged, and a program interruption for
floating-point divide occurs. When the dividend frac
tion is zero, the quotient fraction will be zero. The
quotient sign and characteristic are made zero, yield
ing a true zero result without taking the program
interruption for exponent underflow and exponent
overflow. The program interruption for significance is
never taken for division.
Condition Code: The code remains unchanged.Program Interruptions: Operation (if floating-point feature is not in-
stalled)
Addressing (DD and DE only)
Specification
Exponent overflow
Exponent underflow
Floating-point divide
fraction are made zero, and a program interruption
occurs if the corresponding mask bit is one. Underflow
is not signaled when an operand's characteristics be
come less than zero during prenormalization, and the
correct characteristic and fraction value are used in
the multiplication.
When all 14 result fraction digits are zero, the prod
uct sign and characteristic are made zero, yielding a
true zero result without exponent underflow and ex
ponent overflow causing a program interruption. The
program interruption for lost significance is never
taken for multiplication.
stalled)
Addressing ( MD and ME only)
Specification
Exponent overflow
Exponent underflow
Programming Note
Interchanging the two operands in a floating-point
multiplication does not affect the value of the product.
Divide
DER RR. (Short Operands)
30
78 11 12 15
DE RX (Short Operands)
2
DDR RR (Long Operands)
DD
2
48
The dividend (the first operand) is divided by the
divisor (the second operand) and replaced by the
quotient. No remainder is preserved.
In short-precision, the low-order halves of the float
ing-point register are ignored and remain unchanged.
A floating-point division consists of a characteristic
subtraction and a fraction division. The difference be
tween thc dividend and divisor characteristics plus
64 is used as an intermediate quotient characteristic.
The sign of the quotient is determined by the rules of
algebra.
The quotient fraction is normalized by prenormaliz
ing the operands. Postnormalizing the intermediate
quotient is never necessary, but a right-shift may be
called for. The intermediate-quotient characteristic is
adjusted for the shifts. All dividend fraction digits
participate in forming the quotient, even if the normal
ized dividend fraction is larger than the normalized
divisor fraction. The quotient fraction is truncated to
the desired number of digits.
A program interruption for exponent overflow oc
curs when the final-quotient characteristic exceeds 127.
The operation is terminated.
A program interruption for exponent underflow oc
curs if the final-quotient characteristic is less than
zero. The characteristic, sign, and fraction are made
zero, and the interruption occurs if the corresponding
mask bit is one. Underflow is not signaled for the
intermediate quotient or for the operand character
istics during prenormalization.
When division by a divisor with zero fraction is at
tempted, the opcration is suppressed. The dividend
remains unchanged, and a program interruption for
floating-point divide occurs. When the dividend frac
tion is zero, the quotient fraction will be zero. The
quotient sign and characteristic are made zero, yield
ing a true zero result without taking the program
interruption for exponent underflow and exponent
overflow. The program interruption for significance is
never taken for division.
Condition Code: The code remains unchanged.
stalled)
Addressing (DD and DE only)
Specification
Exponent overflow
Exponent underflow
Floating-point divide