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[Qemu-devel] [PATCH v3 0/6] tcg/mips: Minimal R6 support
From: |
James Hogan |
Subject: |
[Qemu-devel] [PATCH v3 0/6] tcg/mips: Minimal R6 support |
Date: |
Fri, 2 Oct 2015 13:24:11 +0100 |
This patchset adds minimal MIPS r6 host support to TCG.
The first two patches are things I've noticed along the way, and are
independent of the other patches.
Patches 3-6 add R6 awareness to the most important operations, such that
instructions removed in R6 don't get emitted. This seems to be enough to
get a MIPS Linux guest booting on a MIPSr6 host (such as QEMU or I6400).
There are no doubt other improvements that could be made to better
utilise new R6 instruction encodings, but that can wait until a later
patchset.
The R6 changes are basically:
- Patch 4: Don't use the MIPSr5 JR encoding (r6 uses JALR with rd=zero).
- Patch 5: Don't use LO/HI registers, instead using the new
multiply/divide encodings, which map nicely to TCG ops anyway.
- Patch 6: Don't use MOVN/MOVZ instructions. Instead use
SELEQZ/SELNEZ.
Changes in v3:
- Patch 2: Whoops. Fix jr.hb r6 encoding (Leon)
- Patch 6: Switch to using bool eqz to indicate whether to use SELEQZ /
MOVZ instead of SELNEZ / MOVN (Richard).
- Patch 6: Add tcg_debug_assert(v2 == ret) for pre-r6 case with comment
to remind reader that it should be guaranteed via constraints
(Richard).
- Add Richard's Reviewed-by to patch 2, 5, and Leon's to patch 2
Changes in v2:
- Patch 4: Turn #define into enum (Richard).
- Patch 5: Use a common OPC_MUL definition. use_mips32_instructions will
always be 1 for MIPS r6 builds (Richard)
- Combine with patch 6 & 7 from v1, and drop functional changes to
movcond implementation pre-r6. We now provide different constraints
for movcond depending on presence of r6. (thanks Richard for
feedback).
- Add Richard's Reviewed-by to patches 1, 3, 4.
James Hogan (6):
tcg-opc.h: Simplify debug_insn_start def
disas/mips: Add R6 jr/jr.hb to disassembler
tcg/mips: Add use_mips32r6_instructions definition
tcg/mips: Support r6 JR encoding
tcg/mips: Support r6 multiply/divide encodings
tcg/mips: Support r6 SEL{NE,EQ}Z instead of MOVN/MOVZ
disas/mips.c | 2 ++
tcg/mips/tcg-target.c | 90 ++++++++++++++++++++++++++++++++++++++++++++++-----
tcg/mips/tcg-target.h | 11 +++++--
tcg/tcg-opc.h | 12 +++----
4 files changed, 97 insertions(+), 18 deletions(-)
Cc: Aurelien Jarno <address@hidden>
Cc: Richard Henderson <address@hidden>
Cc: Leon Alrae <address@hidden>
--
2.4.9