c.lw

Load word

This instruction is defined by:

Encoding

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Synopsis

Loads a 32-bit value from memory into register xd. It computes an effective address by adding the zero-extended offset, scaled by 4, to the base address in register xs1. It expands to lw xd, offset(xs1).

Access

M

HS

U

VS

VU

Always

Always

Always

Always

Always

Decode Variables

Bits<7> imm = {$encoding[5], $encoding[12:10], $encoding[6], 2'd0};
Bits<3> xd = $encoding[4:2];
Bits<3> xs1 = $encoding[9:7];

Execution

  • Pruned, XLEN == 64

  • Original

if ((misa.C == 1'b0)) {
  raise(ExceptionCode::IllegalInstruction, mode(), $encoding);
}
XReg virtual_address = X[creg2reg(xs1)] + imm;
X[creg2reg(xd)] = sext(read_memory<32>(virtual_address, $encoding), 32);
if (implemented?(ExtensionName::C) && (misa.C == 1'b0)) {
  raise(ExceptionCode::IllegalInstruction, mode(), $encoding);
}
XReg virtual_address = X[creg2reg(xs1)] + imm;
X[creg2reg(xd)] = sext(read_memory<32>(virtual_address, $encoding), 32);

Exceptions

This instruction may result in the following synchronous exceptions:

  • IllegalInstruction

  • LoadAccessFault

  • LoadPageFault