3-262
INSTRUCTION SET REFERENCE
FSUBR/FSUBRP/FISUBRReverse Subtract (Continued)
NOTES:
FMeans finite-real number.
IMeans integer.
*Indicates floating-point invalid-arithmetic-operand (#IA) exception.
Operation
IF instruction is FISUBR
THEN
DEST
<
ConvertExtendedReal(SRC)
?
DEST;
ELSE (* source operand is real number *)
DEST
<
SRC
?
DEST;
FI;
IF instruction = FSUBRP
THEN
PopRegisterStack
FI;
FPU Flags Affected
C1
Set to 0 if stack underflow occurred.
Indicates rounding direction if the inexact result exception (#P) fault is
generated: 0 = not roundup; 1 = roundup.
C0, C2, C3
Undefined.
SRC
???
F or
?
I
?
0
+
0
+
F or +I+
?
NaN
??
*
+
?
+
?
+
?
+
?
+
?
NaN
?
F
??±
F or
±
0
?
DEST
?
DEST
+
F
+
?
NaN
DEST
?
0
??
SRC
±
0
+0SRC
+
?
NaN
+
0
??
SRC
?
0
±
0SRC
+
?
NaN
+
F
??
?
F
?
DEST
?
DEST
±
F or
±
0
+
?
NaN
+
?
??
??
??
??
??
*NaN
NaNNaNNaNNaNNaNNaNNaNNaN