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Release 1.0, 1 July 2002 F. Chapter 5 Registers 19
else if (<FPop commits with IEEE_754_exception>)
<set one bit in the CEXC field as supplied by FPU>;
else if (<FPop commits with unfinished_FPop error>)
<no change>;
else if (<FPop commits with unimplemented_FPop error>)
<no change>;
else
<no change>;
FSR Conformance
SPARC V9 allows the TEM, cexc, and aexc fields to be implemented in hardware in
either of two ways (both of which comply with IEEE Std 754-1985). SPARC64 V
follows case (1); that is, it implements all three fields in conformance with IEEE Std
754-1985. See FSR Conformance in Section 5.1.7 of Commonality for more
information about other implementation methods.
5.1.9 Tick (TICK) Register
SPARC64 V implements TICK.counter register as a 63-bit register (impl. dep.
#105).
Implementation Note –
On SPARC64 V, the counter part of the value returned
when the TICK register is read is the value of TICK.counter when the RDTICK
instruction is executed. The difference between the counter values read from the
TICK register on two reads reflects the number of processor cycles executed between
the executions of the RDTICK instructions, not their commits. In longer code
sequences, the difference between this value and the value that would have been
obtained when the instructions are committed would have been small.
5.2 Privileged Registers
Please refer to Section 5.2 of Commonality for the description of privileged registers.
5.2.6 Trap State (TSTATE) Register
SPARC64 V implements only bits 2:0 of the TSTATE.CWP field. Writes to bits 4 and 3
are ignored, and reads of these bits always return zeroes.