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Simplify go's LUT #332

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Simplify go's LUT #332

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32 changes: 6 additions & 26 deletions go_utils.py
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Original file line number Diff line number Diff line change
Expand Up @@ -19,43 +19,23 @@ def make_go(instr_dict: InstrDict):

import "cmd/internal/obj"

type inst struct {
opcode uint32
funct3 uint32
rs1 uint32
rs2 uint32
csr int64
funct7 uint32
}

func encode(a obj.As) *inst {
// matchFor returns the fixed bits for the given As.
func matchFor(a obj.As) (_ uint32, found bool) {
switch a {
"""

endoffile = """ }
return nil
endoffile = """ }
return 0, false
}
"""

instr_str = ""
for i in instr_dict:
enc_match = int(instr_dict[i]["match"], 0)
opcode = (enc_match >> 0) & ((1 << 7) - 1)
funct3 = (enc_match >> 12) & ((1 << 3) - 1)
rs1 = (enc_match >> 15) & ((1 << 5) - 1)
rs2 = (enc_match >> 20) & ((1 << 5) - 1)
csr = (enc_match >> 20) & ((1 << 12) - 1)
funct7 = (enc_match >> 25) & ((1 << 7) - 1)
instr_str += f""" case A{i.upper().replace("_","")}:
return &inst{{ {hex(opcode)}, {hex(funct3)}, {hex(rs1)}, {hex(rs2)}, {signed(csr,12)}, {hex(funct7)} }}
instr_str += f""" case A{i.upper().replace("_","")}:
return {hex(int(instr_dict[i]["match"], 0))}, true
"""

with open("inst.go", "w", encoding="utf-8") as file:
file.write(prelude)
file.write(instr_str)
file.write(endoffile)

try:
subprocess.run(["go", "fmt", "inst.go"], check=True)
except: # pylint: disable=bare-except
pass