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Add RISC-V encodings for supported icmp variants.

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Only slt and ult variants are in the instruction set. Other condition
codes must be synthesized.
This commit is contained in:
Jakob Stoklund Olesen
2017-03-31 12:12:09 -07:00
parent 75b156e1c7
commit e9907fbdd6
5 changed files with 69 additions and 23 deletions
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15
lib/cretonne/meta/isa/riscv/encodings.py
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@@ -3,9 +3,15 @@ RISC-V Encodings.
"""
from __future__ import absolute_import
from base import instructions as base
from base.immediates import intcc
from .defs import RV32, RV64
from .recipes import OPIMM, OPIMM32, OP, OP32, JALR, R, Rshamt, I, Iret
from .recipes import OPIMM, OPIMM32, OP, OP32, JALR, R, Rshamt, Ricmp, I, Iret
from .settings import use_m
from cdsl.ast import Var
# Dummies for instruction predicates.
x = Var('x')
y = Var('y')
# Basic arithmetic binary instructions are encoded in an R-type instruction.
for inst, inst_imm, f3, f7 in [
@@ -47,6 +53,13 @@ for inst, inst_imm, f3, f7 in [
RV64.enc(inst_imm.i64, Rshamt, OPIMM(f3, f7))
RV64.enc(inst_imm.i32, Rshamt, OPIMM32(f3, f7))
# Signed and unsigned integer 'less than'. There are no 'w' variants for
# comparing 32-bit numbers in RV64.
RV32.enc(base.icmp.i32(intcc.slt, x, y), Ricmp, OP(0b010, 0b0000000))
RV64.enc(base.icmp.i64(intcc.slt, x, y), Ricmp, OP(0b010, 0b0000000))
RV32.enc(base.icmp.i32(intcc.ult, x, y), Ricmp, OP(0b011, 0b0000000))
RV64.enc(base.icmp.i64(intcc.ult, x, y), Ricmp, OP(0b011, 0b0000000))
# "M" Standard Extension for Integer Multiplication and Division.
# Gated by the `use_m` flag.
RV32.enc(base.imul.i32, R, OP(0b000, 0b0000001), isap=use_m)

5
lib/cretonne/meta/isa/riscv/recipes.py
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@@ -11,7 +11,7 @@ instruction formats described in the reference:
from __future__ import absolute_import
from cdsl.isa import EncRecipe
from cdsl.predicates import IsSignedInt
from base.formats import Binary, BinaryImm, MultiAry
from base.formats import Binary, BinaryImm, MultiAry, IntCompare
from .registers import GPR
# The low 7 bits of a RISC-V instruction is the base opcode. All 32-bit
@@ -79,6 +79,9 @@ R = EncRecipe('R', Binary, ins=(GPR, GPR), outs=GPR)
# R-type with an immediate shift amount instead of rs2.
Rshamt = EncRecipe('Rshamt', BinaryImm, ins=GPR, outs=GPR)
# R-type encoding of an integer comparison.
Ricmp = EncRecipe('Ricmp', IntCompare, ins=(GPR, GPR), outs=GPR)
I = EncRecipe(
'I', BinaryImm, ins=GPR, outs=GPR,
instp=IsSignedInt(BinaryImm.imm, 12))