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 FPU condition codes                           O/U# = stack over/underflow if
 (status word bits 14,10,9,8)                         stack exception bit set

                        +-------------------------------+
 Instruction            |  C3   |  C2   |  C1   |  C0   | Interpretation
 -----------------------+-------------------------------+--------------------
 FCOM, FCOMP, FCOMPP,   |                   1           | Zero result or O/U#
 FUCOM, FUCOMP,         |   0       0               0   | ST > operand
 FUCOMPP, FICOM,        |   0       0               1   | ST < operand
 FICOMP, FTST           |   1       0               0   | ST = operand
                        |   1       1               1   | Undefined/unordered
                        |           1                   | Not comparable
 -----------------------+-------------------------------+--------------------
 FCOMI, FCOMIP,         |               |   1   | Unde- | O/U#
 FUCOMI, FUCOMIP        |   Undefined   |       | fined |
 -----------------------+-------------------------------+--------------------
 FXAM                   |                   1           | Sign or O/U#
                        |   0       0       0       0   | +Unnormalized
                        |   0       0       1       0   | -Unnormalized
                        |   0       1       0       0   | +Normalized
                        |   0       1       1       0   | -Normalized
                        |   1       0       0       0   | +0
                        |   1       0       1       0   | -0
                        |   1       1       0       0   | +Denormalized
                        |   1       1       1       0   | -Denormalized
                        |   0       0       0       1   | +NaN
                        |   0       0       1       1   | -NaN
                        |   0       1       0       1   | +Infinity
                        |   0       1       1       1   | -Infinity
                        |   1                       1   | Empty register
 -----------------------+-------------------------------+--------------------
 FABS, FCHS, FXCH,      |               |   1   |       | Zero result or O/U#
 FDECSTP, FINCSTP,      |               |       |       |
 FXTRACT, FLD, FILD,    |   Undefined   |       | Unde- |
 FBLD, FSTP (80 bit),   |               |       | fined |
 constant loads         |               |       |       |
 -----------------------+---------------+-------+-------+--------------------
 FST, FSTP (< 80 bit),  |               |   1   |       | Roundup or O/U#
 FBST, FIST, FRNDINT,   |               |       |       |
 FADD, FDIV, FDIVR,     |               |       |       |
 FMUL, FSUB, FSUBR,     |   Undefined   |       | Unde- |
 F2XM1, FPATAN, FSCALE, |               |       | fined |
 FSQRT, FYL2X, FYL2XP1, |               |       |       |
 FCMOVcc                |               |       |       |
 -----------------------+-----------------------+-------+--------------------
 FPTAN, FSIN, FCOS,     |       |   0           |       | Reduction complete
 FSINCOS                | Unde- |   1           | Unde- | Reduction incomplete
                        | fined |           ?   | fined | Undefined if C2=1
                        |       |           1   |       | Roundup or O/U#
 -----------------------+-------------------------------+--------------------
 FPREM, FPREM1          |           0                   | Reduction complete
                        |           1                   | Reduction incomplete
                        |                   1           | O/U#
                        |  Q0              Q1      Q2   | Quotient L.O. bits
 -----------------------+-------------------------------+--------------------
 FLDENV, FRSTOR         |       Loaded from memory      |
 -----------------------+-------------------------------+--------------------
 FINIT, FSAVE           |         Cleared to zero       |
 -----------------------+-------------------------------+--------------------
 FLDCW, FSTCW, FSTSW,   |                               |
 FSTENV, FCLEX          |           Undefined           |
 -----------------------+-------------------------------+--------------------
                        |  C3   |  C2   |  C1   |  C0   |
                        +-------------------------------+