On Thu, Jun 16, 2016 at 11:04:12PM -0500, Segher Boessenkool wrote:
On Fri, Jun 17, 2016 at 09:33:45AM +1000, Chris Smart wrote:
+#define PPC_INST_COPY 0x7c00060c
+#define PPC_INST_COPY_FIRST 0x7c20060c
+#define PPC_INST_PASTE 0x7c00070c
+#define PPC_INST_PASTE_LAST 0x7c20070d
That's not quite right I think.
Hi Segher,
Thanks for checking that for me, it's good to make sure it's correct.
Just to be sure, I've gone back and compared them all with the ISA. I
think that the only one that differs is the paste_last. Am I missing
something?
copy is 7c00060c mask fc2007fe (or ffe007fe)
COPY = copy RA,RB,L (L=0)
31 //// L RA RB 774 /
011111 0000 0 00000 00000 1100000110 0 = 0x7c00060c (instruction)
111111 0000 1 00000 00000 1111111111 0 = 0xfc2007fe (specific mask)
copy_first is 7c20060c mask fc2007fe
COPY_FIRST = copy RA,RB,L (L=1)
If L=1, the instruction identifies the beginning of a move group.
31 //// L RA RB 774 /
011111 0000 1 00000 00000 1100000110 0 = 0x7c20060c (instruction)
111111 0000 1 00000 00000 1111111111 0 = 0xfc2007fe (specific mask)
paste is 7c00070c mask fc2007fe
PASTE = paste RA,RB,L (L=0 Rc=0)
31 //// L RA RB 902 Rc
011111 0000 0 00000 00000 1110000110 0 = 0x7c00070c (instruction)
111111 0000 1 00000 00000 1111111111 1 = 0xfc2007ff (specific mask)
paste_last is 7c20070c mask fc2007fe
PASTE_LAST = paste. RA,RB,L (L=1 Rc=1)
If L=1, the instruction identifies the end of a move group.
If L≠Rc, the instruction form is invalid.
31 //// L RA RB 902 Rc
011111 0000 1 00000 00000 1110000110 1 = 0x7c20070d (instruction)
111111 0000 1 00000 00000 1111111111 1 = 0xfc2007ff (specific mask)
(this includes record form for paste; the low bit).
To make the test simple I use a combined copy, copy_first, paste and
paste_last mask to compare just against copy. So that excluded:
- L
- bit 24 of 32
- Rc
111111 0000 0 00000 00000 1101111111 0 = 0xfc0006fe
Would it be better and more clear to check each instruction with its
mask? Something like:
#define PPC_INST_COPY_MASK 0xfc2007fe
#define PPC_INST_PASTE_MASK 0xfc2007ff
if (cpu_has_feature(CPU_FTR_ARCH_300)) {
unsigned int masked_instruction = instruction & PPC_INST_COPY_MASK;
if (masked_instruction == PPC_INST_COPY || \
masked_instruction == PPC_INST_COPY_FIRST)
return -EIO;
masked_instruction = instruction & PPC_INST_PASTE_MASK;
if (masked_instruction == PPC_INST_PASTE || \
masked_instruction == PPC_INST_PASTE_LAST)
return -EIO;
}
Thanks!
-c
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