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[Qemu-devel] [PULL 24/32] tcg: Clean up generic bswap64
From: |
Richard Henderson |
Subject: |
[Qemu-devel] [PULL 24/32] tcg: Clean up generic bswap64 |
Date: |
Thu, 13 Dec 2018 21:19:15 -0600 |
Based on the only current user, Sparc:
New code uses 2 constants that take 2 insns to load from constant pool,
plus 13. Old code used 6 constants that took 1 or 2 insns to create,
plus 21. The result is a new total of 17 vs an old total of 29.
Signed-off-by: Richard Henderson <address@hidden>
---
tcg/tcg-op.c | 43 ++++++++++++++++++-------------------------
1 file changed, 18 insertions(+), 25 deletions(-)
diff --git a/tcg/tcg-op.c b/tcg/tcg-op.c
index a956499e46..887b371a81 100644
--- a/tcg/tcg-op.c
+++ b/tcg/tcg-op.c
@@ -1678,37 +1678,30 @@ void tcg_gen_bswap64_i64(TCGv_i64 ret, TCGv_i64 arg)
} else {
TCGv_i64 t0 = tcg_temp_new_i64();
TCGv_i64 t1 = tcg_temp_new_i64();
+ TCGv_i64 t2 = tcg_temp_new_i64();
- tcg_gen_shli_i64(t0, arg, 56);
+ /* arg = abcdefgh */
+ tcg_gen_movi_i64(t2, 0x00ff00ff00ff00ffull);
+ tcg_gen_shri_i64(t0, arg, 8); /* t0 = .abcdefg */
+ tcg_gen_and_i64(t1, arg, t2); /* t1 = .b.d.f.h */
+ tcg_gen_and_i64(t0, t0, t2); /* t0 = .a.c.e.g */
+ tcg_gen_shli_i64(t1, t1, 8); /* t1 = b.d.f.h. */
+ tcg_gen_or_i64(ret, t0, t1); /* ret = badcfehg */
- tcg_gen_andi_i64(t1, arg, 0x0000ff00);
- tcg_gen_shli_i64(t1, t1, 40);
- tcg_gen_or_i64(t0, t0, t1);
+ tcg_gen_movi_i64(t2, 0x0000ffff0000ffffull);
+ tcg_gen_shri_i64(t0, ret, 16); /* t0 = ..badcfe */
+ tcg_gen_and_i64(t1, ret, t2); /* t1 = ..dc..hg */
+ tcg_gen_and_i64(t0, t0, t2); /* t0 = ..ba..fe */
+ tcg_gen_shli_i64(t1, t1, 16); /* t1 = dc..hg.. */
+ tcg_gen_or_i64(ret, t0, t1); /* ret = dcbahgfe */
- tcg_gen_andi_i64(t1, arg, 0x00ff0000);
- tcg_gen_shli_i64(t1, t1, 24);
- tcg_gen_or_i64(t0, t0, t1);
+ tcg_gen_shri_i64(t0, ret, 32); /* t0 = ....dcba */
+ tcg_gen_shli_i64(t1, ret, 32); /* t1 = hgfe.... */
+ tcg_gen_or_i64(ret, t0, t1); /* ret = hgfedcba */
- tcg_gen_andi_i64(t1, arg, 0xff000000);
- tcg_gen_shli_i64(t1, t1, 8);
- tcg_gen_or_i64(t0, t0, t1);
-
- tcg_gen_shri_i64(t1, arg, 8);
- tcg_gen_andi_i64(t1, t1, 0xff000000);
- tcg_gen_or_i64(t0, t0, t1);
-
- tcg_gen_shri_i64(t1, arg, 24);
- tcg_gen_andi_i64(t1, t1, 0x00ff0000);
- tcg_gen_or_i64(t0, t0, t1);
-
- tcg_gen_shri_i64(t1, arg, 40);
- tcg_gen_andi_i64(t1, t1, 0x0000ff00);
- tcg_gen_or_i64(t0, t0, t1);
-
- tcg_gen_shri_i64(t1, arg, 56);
- tcg_gen_or_i64(ret, t0, t1);
tcg_temp_free_i64(t0);
tcg_temp_free_i64(t1);
+ tcg_temp_free_i64(t2);
}
}
--
2.17.2
- [Qemu-devel] [PULL 13/32] tcg/aarch64: Return false on failure from patch_reloc, (continued)
- [Qemu-devel] [PULL 13/32] tcg/aarch64: Return false on failure from patch_reloc, Richard Henderson, 2018/12/13
- [Qemu-devel] [PULL 15/32] tcg/ppc: Return false on failure from patch_reloc, Richard Henderson, 2018/12/13
- [Qemu-devel] [PULL 17/32] tcg/i386: Propagate is64 to tcg_out_qemu_ld_direct, Richard Henderson, 2018/12/13
- [Qemu-devel] [PULL 16/32] tcg/s390x: Return false on failure from patch_reloc, Richard Henderson, 2018/12/13
- [Qemu-devel] [PULL 19/32] tcg/i386: Implement INDEX_op_extr{lh}_i64_i32 for 32-bit guests, Richard Henderson, 2018/12/13
- [Qemu-devel] [PULL 18/32] tcg/i386: Propagate is64 to tcg_out_qemu_ld_slow_path, Richard Henderson, 2018/12/13
- [Qemu-devel] [PULL 21/32] tcg/i386: Precompute all guest_base parameters, Richard Henderson, 2018/12/13
- [Qemu-devel] [PULL 23/32] tcg: Clean up generic bswap32, Richard Henderson, 2018/12/13
- [Qemu-devel] [PULL 29/32] qht-bench: document -p flag, Richard Henderson, 2018/12/13
- [Qemu-devel] [PULL 22/32] tcg/i386: Add setup_guest_base_seg for FreeBSD, Richard Henderson, 2018/12/13
- [Qemu-devel] [PULL 24/32] tcg: Clean up generic bswap64,
Richard Henderson <=
- [Qemu-devel] [PULL 20/32] tcg/i386: Assume 32-bit values are zero-extended, Richard Henderson, 2018/12/13
- [Qemu-devel] [PULL 31/32] include: move exec/tb-hash-xx.h to qemu/xxhash.h, Richard Henderson, 2018/12/13
- [Qemu-devel] [PULL 32/32] xxhash: match output against the original xxhash32, Richard Henderson, 2018/12/13
- [Qemu-devel] [PULL 27/32] tcg/mips: Improve the add2/sub2 command to use TCG_TARGET_REG_BITS, Richard Henderson, 2018/12/13
- [Qemu-devel] [PULL 28/32] tcg: Drop nargs from tcg_op_insert_{before, after}, Richard Henderson, 2018/12/13
- [Qemu-devel] [PULL 26/32] tcg: Add TCG_TARGET_HAS_MEMORY_BSWAP, Richard Henderson, 2018/12/13
- [Qemu-devel] [PULL 25/32] tcg/optimize: Optimize bswap, Richard Henderson, 2018/12/13
- [Qemu-devel] [PULL 30/32] exec: introduce qemu_xxhash{2,4,5,6,7}, Richard Henderson, 2018/12/13
- Re: [Qemu-devel] [PULL 00/32] tcg patch queue, Peter Maydell, 2018/12/15