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INSTRUCTION SET REFERENCE
FPATAN—Partial Arctangent (Continued)
Intel Architecture Compatibility
The source operands for this instruction are restricted for the 80287 math coprocessor to the
following range:
0
?
|ST(1)|
<
|ST(0)|
<
+?
Operation
ST(1)
<
arctan(ST(1) / ST(0));
PopRegisterStack;
FPU Flags Affected
C1
Set to 0 if stack underflow occurred.
Indicates rounding direction if the inexact result exception (#P) is gener-
ated: 0 = not roundup; 1 = roundup.
C0, C2, C3
Undefined.
Floating-Point Exceptions
#IS
Stack underflow occurred.
#IA
Source operand is an sNaN value or unsupported format.
#D
Source operand is a denormal value.
#U
Result is too small for destination format.
#P
Value cannot be represented exactly in destination format.
Protected Mode Exceptions
#NM
EM or TS in CR0 is set.
Real-Address Mode Exceptions
#NM
EM or TS in CR0 is set.
Virtual-8086 Mode Exceptions
#NM
EM or TS in CR0 is set.
