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arch-power: Add population count instructions

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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 <sandipan@linux.ibm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/40921
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 17:21:23 +05:30
parent 99495afb20
commit f9653e7685
1 changed files with 42 additions and 1 deletions
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43
src/arch/power/isa/decoder.isa
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@@ -288,7 +288,23 @@ decode PO default Unknown::unknown() {
}
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 @@ decode PO default Unknown::unknown() {
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 @@ decode PO default Unknown::unknown() {
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;