3-223
INSTRUCTION SET REFERENCE
FPREM—Partial Remainder
Description
This instruction computes the remainder obtained from dividing the value in the ST(0) register
(the dividend) by the value in the ST(1) register (the divisor or modulus), and stores the result
in ST(0). The remainder represents the following value:
Remainder = ST(0)
?
(Q
?
ST(1))
Here, Q is an integer value that is obtained by truncating the real-number quotient of [ST(0) /
ST(1)] toward zero. The sign of the remainder is the same as the sign of the dividend. The
magnitude of the remainder is less than that of the modulus, unless a partial remainder was
computed (as described below).
This instruction produces an exact result; the precision (inexact) exception does not occur and
the rounding control has no effect. The following table shows the results obtained when
computing the remainder of various classes of numbers, assuming that underflow does not
occur.
NOTES:
FMeans finite-real number.
*Indicates floating-point invalid-arithmetic-operand (#IA) exception.
**Indicates floating-point zero-divide (#Z) exception.
When the result is 0, its sign is the same as that of the dividend. When the modulus is
?
, the
result is equal to the value in ST(0).
Opcode
Instruction
Description
D9 F8
FPREM
Replace ST(0) with the remainder obtained from
dividing ST(0) by ST(1)
ST(1)
??
?
F
?
0
+
0
+
F
+
?
NaN
??
*
*
*
*
*
*NaN
ST(0)
?
FST(0)
?
F or
?
0**
**
?
F or
?
0ST(0)NaN
?
0
?
0
?
0
*
*
?
0
?
0NaN
+
0
+0
+0
*
*
+0
+0NaN
+
FST(0)
+
F or +0**
**
+
F or +0ST(0)NaN
+
?
*
*
*
*
*
*NaN
NaNNaNNaNNaNNaNNaNNaNNaN
