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arch-power: Add character compare instructions

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This adds the following instructions.
  * Compare Ranged Byte (cmprb)
  * Compare Equal Byte (cmpeqb)

Change-Id: I12a9135bf302acd741abe27cb557e8e8bba82edc
Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/40915
Reviewed-by: Boris Shingarov <shingarov@labware.com>
Maintainer: Boris Shingarov <shingarov@labware.com>
Tested-by: kokoro <noreply+kokoro@google.com>
This commit is contained in:
Sandipan Das
2021-02-06 17:21:00 +05:30
parent 5a9d543311
commit 9931e7ce0d
2 changed files with 25 additions and 1 deletions
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24
src/arch/power/isa/decoder.isa
View File

@@ -313,6 +313,20 @@ decode PO default Unknown::unknown() {
183: stwux({{ Mem_uw = Rs_uw; }});
}
192: IntCompOp::cmprb({{
uint32_t src1 = Ra_ub;
uint32_t src2 = Rb_uw;
uint8_t src2lo = src2 & 0xff;
uint8_t src2hi = (src2 >>= 8) & 0xff;
uint32_t res = (src2lo <= src1) & (src1 <= src2hi);
if (l) {
src2lo = (src2 >>= 8) & 0xff;
src2hi = (src2 >>= 8) & 0xff;
res = ((src2lo <= src1) & (src1 <= src2hi)) | res;
}
cr = res << 2;
}});
format StoreIndexOp {
214: stdcx({{
bool store_performed = false;
@@ -334,6 +348,16 @@ decode PO default Unknown::unknown() {
215: stbx({{ Mem_ub = Rs_ub; }});
}
224: IntCompOp::cmpeqb({{
// Based on "Determine if a word has a byte equal to n"
// from https://graphics.stanford.edu/~seander/bithacks.html
const uint64_t m1 = 0x0101010101010101;
const uint64_t m2 = 0x8080808080808080;
uint64_t res = Rb ^ (Ra_ub * m1);
res = (res - m1) & ~res & m2;
cr = (res != 0) << 2;
}});
246: MiscOp::dcbtst({{ }});
247: StoreIndexUpdateOp::stbux({{ Mem_ub = Rs_ub; }});

2
src/arch/power/isa/formats/integer.isa
View File

@@ -33,7 +33,7 @@
let {{
readXERCode = 'Xer xer = XER;'
readXERCode = 'GEM5_VAR_USED Xer xer = XER;'
setXERCode = 'XER = xer;'