Decimal Instructions - Xerox 560 Reference Manual

FMS FLOATING MULTIPLY SHORT
(yVord index alignment)
H
3F
I
R
I
X
I:
Referenc~
address
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The effective word (multiplier) and the contents of register R
(multiplicand) are loaded into a set of internal registers,
and both numbers are then prenormalized (if necessary). A
normalized 6-digit product is produced, appended by a
guard digit. If FR equals 1, and the guard digit contains 8
or greater, the fraction is incremented.
If
no floating-
point arithmetic fault occurs, the product is loaded into
register R as a short-format floating-point number.
Affected: (R), CC
(R)
x
EW-R
Trap: Floating-point arith-
metic fault
FML
FLOATING MULTIPLY LONG
(Doubleword index alignment)
The effective doubleword (multiplier) and the contents of
registers Rand Ru1 (multiplicand) are loaded into a set of
internal registers. (FLOATING MULTIPLY LONG then
operates identically to FLOATING MULTIPLY SHORT
(FMS), except that the operands are each 14 hexadecimal
digits long. R must be an even value for correct results.
If no floating-point arithmetic fault occurs, the product is
loaded into registers Rand Ru1 as a long-format floating-
point number.
Affected: (R), (Ru1), CC
(R, Ru1) x ED - R , Rul
Trap: Floating-point arith-
metic fault, instruc-
tion exception
The R field of the FML instruction must be an even value
for proper operation of the instruction; if the R field of
FML is an odd value, the instruction traps to location X'4D',
instruction exception trap.
FOS
FLOATING DIVIDE SHORT
(Word index alignment)
The effective word (divisor) and the contents of register R
(dividend) are loaded into a set of internal registers and
both numbers are then prenormalized (if necessary). A
normalized 6-digit quotient is produced, appended by a
guard digit.
If
FR equals 1, and the guard digit contains
8
or greater, the fraction is incremented. If no floating-
point arithmetic fault occurs, the quotient is loaded into
register R as a short-format floating-point number.
Affected: (R), CC
(R).;. EW-R
80 Decimal Instructions
Trap: Floating-point arith-
metic fault
FOL
FLOATING DNIDE LONG
(Doubleword index alignment)
The effective doubleword (divisor) and the contents of
registers Rand Rul (dividend) are loaded into a set of
internal registers. FLOATING DIVIDE LONG then oper-
ates identically to FLOATING DIVIDE SHORT (FDS), ex-
cept that the operands are each 14 hexadecimal digits long.
R must be an even value for correct results.
If
no floating-
point arithmetic fault occurs, the quotient is loaded into
registers Rand Ru1 as a long-format floating-point number.
Affected: (R), (Rul), CC
(R, Ru1}.;. ED-R, Ru1
Trap: Floating-point arith-
metic fault,
instruc~
tion exception
The R field of the FDL instruction must be an even value
for proper operation of the instruction; if the R field of FDL
is an odd value, the instruction traps to location X'4D'
instruction exception trap.
DECIMAL INSTRUCTIONS
The following instructions comprise the decimal instruction
set:
Instruction Name
Decimal Load
Decimal Store
Decimal Add
Decimal Subtract
Decimal Multiply
Decimal Divide
Decimal Compare
Decimal Shift Arithmetic
Pack Decimal Digits
Unpack Decimal Digits
Edit Byte String (described under
"Byte-String Instructions")
Mnemonic
DL
DST
DA
DS
DM
DD
DC
DSA
UNPK
EBS