asm-ppc64/ptrace.h / fscpr

[Paul Mackerras]

Steve Munroe writes:

> #define PT_FPR0 48
> #define PT_FPSCR (PT_FPR0 + 32 + 1)
>
> So how is this wrong? Is the kernel storing the FPSCR in the wrong slot?

No.  Each index references 64 bits.  The 32 FPRs are at PT_FPR0 + 0 ...
PT_FPR0 + 31.  The *next* index, that is PT_FPR0 + 32, contains the
FPSCR in the low 32 bits and junk in the high 32 bits.

The reason for the +1 in the 32-bit case is that the useful bits of
the FPSCR are in the low 32 bits of the 64-bit slot.

Paul.

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