Sandipan Das has submitted this change. (
https://gem5-review.googlesource.com/c/public/gem5/+/40921 )
Change subject: arch-power: Add population count instructions
......................................................................
arch-power: Add population count instructions
This adds the following instructions.
* Population Count Bytes (popcntb)
* Population Count Words (popcntw)
* Population Count Doubleword (popcntd)
Change-Id: Id15188482b45552735c1d960418d5d6ba1f2ede8
Signed-off-by: Sandipan Das <[email protected]>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/40921
Reviewed-by: Boris Shingarov <[email protected]>
Maintainer: Boris Shingarov <[email protected]>
Tested-by: kokoro <[email protected]>
---
M src/arch/power/isa/decoder.isa
1 file changed, 42 insertions(+), 1 deletion(-)
Approvals:
Boris Shingarov: Looks good to me, approved; Looks good to me, approved
kokoro: Regressions pass
diff --git a/src/arch/power/isa/decoder.isa b/src/arch/power/isa/decoder.isa
index 15ad7ad..fdb86f9 100644
--- a/src/arch/power/isa/decoder.isa
+++ b/src/arch/power/isa/decoder.isa
@@ -288,7 +288,23 @@
}
119: LoadIndexUpdateOp::lbzux({{ Rt = Mem_ub; }});
- 124: IntLogicOp::nor({{ Ra = ~(Rs | Rb); }}, true);
+
+ format IntLogicOp {
+ 122: popcntb({{
+ // Based on "Counting bits set, in parallel"
+ // from
https://graphics.stanford.edu/~seander/bithacks.html
+ const uint64_t m1 = 0x5555555555555555ULL;
+ const uint64_t m2 = 0x3333333333333333ULL;
+ const uint64_t m4 = 0x0f0f0f0f0f0f0f0fULL;
+ uint64_t res = Rs;
+ res = (res & m1) + ((res >> 1) & m1);
+ res = (res & m2) + ((res >> 2) & m2);
+ res = (res & m4) + ((res >> 4) & m4);
+ Ra = res;
+ }});
+
+ 124: nor({{ Ra = ~(Rs | Rb); }}, true);
+ }
format StoreIndexOp {
149: stdx({{ Mem = Rs }});
@@ -403,6 +419,30 @@
375: lhaux({{ Rt = Mem_sh; }});
}
+ 378: IntLogicOp::popcntw({{
+ #if defined(__GNUC__) || (defined(__clang__) && \
+ __has_builtin(__builtin_popcount))
+ uint64_t src = Rs;
+ uint64_t res = __builtin_popcount(src >> 32);
+ res = (res << 32) | __builtin_popcount(src);
+ #else
+ // Based on "Counting bits set, in parallel"
+ // from https://graphics.stanford.edu/~seander/bithacks.html
+ const uint64_t m1 = 0x5555555555555555ULL;
+ const uint64_t m2 = 0x3333333333333333ULL;
+ const uint64_t m4 = 0x0f0f0f0f0f0f0f0fULL;
+ const uint64_t m8 = 0x00ff00ff00ff00ffULL;
+ const uint64_t m16 = 0x0000ffff0000ffffULL;
+ uint64_t res = Rs;
+ res = (res & m1) + ((res >> 1) & m1);
+ res = (res & m2) + ((res >> 2) & m2);
+ res = (res & m4) + ((res >> 4) & m4);
+ res = (res & m8) + ((res >> 8) & m8);
+ res = (res & m16) + ((res >> 16) & m16);
+ #endif
+ Ra = res;
+ }});
+
407: StoreIndexOp::sthx({{ Mem_uh = Rs_uh; }});
412: IntLogicOp::orc({{ Ra = Rs | ~Rb; }}, true);
439: StoreIndexUpdateOp::sthux({{ Mem_uh = Rs_uh; }});
@@ -410,6 +450,7 @@
format IntLogicOp {
444: or({{ Ra = Rs | Rb; }}, true);
476: nand({{ Ra = ~(Rs & Rb); }}, true);
+ 506: popcntd({{ Ra = popCount(Rs); }});
508: cmpb({{
uint64_t mask = 0xff;
--
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Gerrit-Project: public/gem5
Gerrit-Branch: develop
Gerrit-Change-Id: Id15188482b45552735c1d960418d5d6ba1f2ede8
Gerrit-Change-Number: 40921
Gerrit-PatchSet: 8
Gerrit-Owner: Sandipan Das <[email protected]>
Gerrit-Reviewer: Boris Shingarov <[email protected]>
Gerrit-Reviewer: Sandipan Das <[email protected]>
Gerrit-Reviewer: kokoro <[email protected]>
Gerrit-MessageType: merged
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