Xilinx MicroBlaze Reference Manual page 230

fcmp Floating-Point Number Comparison
rD, rA, rB
fcmp.un
fcmp.lt rD, rA, rB
rD, rA, rB
fcmp.eq
fcmp.le rD, rA, rB
rD, rA, rB
fcmp.gt
fcmp.ne rD, rA, rB
rD, rA, rB
fcmp.ge
0 1 0 1 1 0
0
6
Description
The floating-point value in rB is compared with the floating-point value in rA and the comparison
result is placed into register rD. The OpSel field in the instruction code determines the type of
comparison performed.
Pseudocode
if isDnz(rA) or isDnz(rB) then
←
(rD) 0
←
FSR[DO]
←
ESR[EC]
else
{read out behavior from
Registers Altered
• rD, unless an FP exception is generated, in which case the register is unchanged
• ESR[EC], if an FP exception is generated
• FSR[IO,DO]
Latency
• 1 cycle with
• 3 cycles with
Note
These instructions are only available when the MicroBlaze parameter C_USE_FPU is greater than 0.
Table 5-2 lists the floating-point comparison operations.
MicroBlaze Processor Reference Guide
UG984 (v2018.2) June 21, 2018
Unordered floating-point comparison
Less-than floating-point comparison
Equal floating-point comparison
Less-or-Equal floating-point comparison
Greater-than floating-point comparison
Not-Equal floating-point comparison
Greater-or-Equal floating-point comparison
rD rA
11
1
00110
Table 5-2}
=0 or 2
C_AREA_OPTIMIZED
=1
C_AREA_OPTIMIZED
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Chapter 5: MicroBlaze Instruction Set Architecture
rB 0 1 0 0 OpSel
16 21
0 0 0 0
25 28 31
231
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