Add SUB instruction

This commit is contained in:
Donald Sebastian Leung 2020-08-04 12:25:12 +08:00
parent aad9a3f2b5
commit 67c57c4d7d
1 changed files with 21 additions and 0 deletions

21
insns/insn_sub.py Normal file
View File

@ -0,0 +1,21 @@
from insn_R import *
class rvfi_insn_sub(rvfi_insn_R):
def __init__(self):
super(rvfi_insn_sub, self).__init__()
def ports(self):
return super(rvfi_insn_sub, self).ports()
def elaborate(self, platform):
m = super(rvfi_insn_sub, self).elaborate(platform)
# SUB instruction
result = Signal(32)
m.d.comb += result.eq(self.rvfi_rs1_rdata - self.rvfi_rs2_rdata)
m.d.comb += self.spec_valid.eq(self.rvfi_valid & (~self.insn_padding) & (self.insn_funct7 == 0b0100000) & (self.insn_funct3 == 0b000) & (self.insn_opcode == 0b0110011))
m.d.comb += self.spec_rs1_addr.eq(self.insn_rs1)
m.d.comb += self.spec_rs2_addr.eq(self.insn_rs2)
m.d.comb += self.spec_rd_addr.eq(self.insn_rd)
m.d.comb += self.spec_rd_wdata.eq(Mux(self.spec_rd_addr, result, 0))
m.d.comb += self.spec_pc_wdata.eq(self.rvfi_pc_rdata + 4)
return m