c.ldsp
Load doubleword from stack pointer
This instruction is defined by:
Synopsis
C.LDSP is an RV64C/RV128C-only instruction that loads a 64-bit value from memory
into register xd.
It computes its effective address by adding the zero-extended offset, scaled by 8,
to the stack pointer, x2.
It expands to ld xd, offset(x2).
C.LDSP is only valid when xd ≠ x0; code points with xd=x0 are reserved.
Decode Variables
Bits<9> imm = {$encoding[4:2], $encoding[12], $encoding[6:5], 3'd0};
Bits<5> xd = $encoding[11:7];Execution
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Pruned, XLEN == 64
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Original
XReg virtual_address = X[2] + imm;
Bits<64> value = read_memory(64, virtual_address, $encoding);
X[xd] = value;if (implemented?(ExtensionName::C) && (CSR[misa].C == 1'b0)) {
raise(ExceptionCode::IllegalInstruction, mode(), $encoding);
}
XReg virtual_address = X[2] + imm;
Bits<64> value = read_memory(64, virtual_address, $encoding);
if (xlen() == 64) {
X[xd] = value;
} else if (xlen() == 32) {
X[xd] = value[31:0];
X[xd + 1] = value[63:32];
}