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