[Qemu-devel] [PATCH v2 0/6] tcg/mips: Minimal R6 support

[James Hogan]

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 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 | 87 ++++++++++++++++++++++++++++++++++++++++++++++-----
 tcg/mips/tcg-target.h | 11 +++++--
 tcg/tcg-opc.h         | 12 +++----
 4 files changed, 94 insertions(+), 18 deletions(-)

Cc: Aurelien Jarno <address@hidden>
Cc: Richard Henderson <address@hidden>
Cc: Leon Alrae <address@hidden>
-- 
2.4.9