FBcc Branch
Conditionally
FBcc
Instruction Fields:
Coprocessor ID Field -- Specifies which coprocessor in the system is to execute this
instruction. Freescale assemblers default to ID = 1 for the FPCP.
Size Field -- Specifies the size of the signed displacement:
If Format=0, then the displacement is 16-bits and is sign extended before use.
If Format = 1, then the displacement is 32-bits.
Conditional Predicate Field -- Specifies one of 32 conditional tests as defined in 4.4
CONDITIONAL TEST DEFINITIONS.
NOTE
When a BSUN exception occurs, the main processor takes a pre-instruction ex-
ception. If the exception handler returns without modifying the image of the PC
on the stack frame (to point to the instruction following the FBcc), then it must
clear the cause of the exception (by clearing the NAN bit or disabling the BSUN
trap) or the exception occurs again immediately upon return to the routine that
caused the exception.
MC68881/MC68882 USER'S MANUAL
FREESCALE
4-31
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