Commit 6176a26d1d0fe40dea0fd6a4e1a437931cbdcb2d
1 parent
182608d4
target-ppc: optimize popcntb
Suggested by Andrzej Zaborowski. Signed-off-by: Aurelien Jarno <aurelien@aurel32.net> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5592 c046a42c-6fe2-441c-8c8c-71466251a162
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8 additions
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14 deletions
target-ppc/op_helper.c
| @@ -222,25 +222,19 @@ target_ulong helper_srad (target_ulong value, target_ulong shift) | @@ -222,25 +222,19 @@ target_ulong helper_srad (target_ulong value, target_ulong shift) | ||
| 222 | 222 | ||
| 223 | target_ulong helper_popcntb (target_ulong val) | 223 | target_ulong helper_popcntb (target_ulong val) |
| 224 | { | 224 | { |
| 225 | - uint32_t ret; | ||
| 226 | - int i; | ||
| 227 | - | ||
| 228 | - ret = 0; | ||
| 229 | - for (i = 0; i < 32; i += 8) | ||
| 230 | - ret |= ctpop8((val >> i) & 0xFF) << i; | ||
| 231 | - return ret; | 225 | + val = (val & 0x55555555) + ((val >> 1) & 0x55555555); |
| 226 | + val = (val & 0x33333333) + ((val >> 2) & 0x33333333); | ||
| 227 | + val = (val & 0x0f0f0f0f) + ((val >> 4) & 0x0f0f0f0f); | ||
| 228 | + return val; | ||
| 232 | } | 229 | } |
| 233 | 230 | ||
| 234 | #if defined(TARGET_PPC64) | 231 | #if defined(TARGET_PPC64) |
| 235 | target_ulong helper_popcntb_64 (target_ulong val) | 232 | target_ulong helper_popcntb_64 (target_ulong val) |
| 236 | { | 233 | { |
| 237 | - uint64_t ret; | ||
| 238 | - int i; | ||
| 239 | - | ||
| 240 | - ret = 0; | ||
| 241 | - for (i = 0; i < 64; i += 8) | ||
| 242 | - ret |= ctpop8((val >> i) & 0xFF) << i; | ||
| 243 | - return ret; | 234 | + val = (val & 0x5555555555555555ULL) + ((val >> 1) & 0x5555555555555555ULL); |
| 235 | + val = (val & 0x3333333333333333ULL) + ((val >> 2) & 0x3333333333333333ULL); | ||
| 236 | + val = (val & 0x0f0f0f0f0f0f0f0fULL) + ((val >> 4) & 0x0f0f0f0f0f0f0f0fULL); | ||
| 237 | + return val; | ||
| 244 | } | 238 | } |
| 245 | #endif | 239 | #endif |
| 246 | 240 |