// Print Vn to align with assembler (e.g., SHA256H)
				return fmt.Sprintf("V%d", regno)
			}

		}
		return plan9gpr(a)

	case RegSP:
		regno := uint16(a) & 31
		if regno == 31 {
			return "RSP"
		}
		return fmt.Sprintf("R%d", regno)

	case RegExtshiftAmount:
		reg := plan9gpr(a.reg)
		extshift := ""
		amount := ""
		if a.extShift != ExtShift(0) {
			switch a.extShift {
			default: