bne
Branch if not equal
This instruction is defined by:
-
I, version >= 0
This instruction is included in the following profiles:
-
RVA20S64 (Mandatory)
-
RVA20U64 (Mandatory)
-
RVA22S64 (Mandatory)
-
RVA22U64 (Mandatory)
Synopsis
Branch to PC + imm if the value in register rs1 is not equal to the value in register rs2.
Raise a MisalignedAddress exception if PC + imm is misaligned.
Decode Variables
Bits<13> imm = {$encoding[31], $encoding[7], $encoding[30:25], $encoding[11:8], 1'd0};
Bits<5> rs2 = $encoding[24:20];
Bits<5> rs1 = $encoding[19:15];Execution
-
IDL
-
Sail
XReg lhs = X[rs1];
XReg rhs = X[rs2];
if (lhs != rhs) {
jump_halfword($pc + imm);
}{
let rs1_val = X(rs1);
let rs2_val = X(rs2);
let taken : bool = match op {
RISCV_BEQ => rs1_val == rs2_val,
RISCV_BNE => rs1_val != rs2_val,
RISCV_BLT => rs1_val <_s rs2_val,
RISCV_BGE => rs1_val >=_s rs2_val,
RISCV_BLTU => rs1_val <_u rs2_val,
RISCV_BGEU => rs1_val >=_u rs2_val
};
let t : xlenbits = PC + sign_extend(imm);
if taken then {
/* Extensions get the first checks on the prospective target address. */
match ext_control_check_pc(t) {
Ext_ControlAddr_Error(e) => {
ext_handle_control_check_error(e);
RETIRE_FAIL
},
Ext_ControlAddr_OK(target) => {
if bit_to_bool(target[1]) & not(extension("C")) then {
handle_mem_exception(target, E_Fetch_Addr_Align());
RETIRE_FAIL;
} else {
set_next_pc(target);
RETIRE_SUCCESS
}
}
}
} else RETIRE_SUCCESS
}