rs1
if (funct == 0b110 && rs1 == 0)
else if (funct == 0b111 && rs1 != 0)
frame->tf_sepc = rs1;
#define rs1_lval (rs1_index != 0 ? rs1 : 0)
uint32_t rd, rs1, rs2, rs3;
rs1 = (insn & RS1_MASK) >> RS1_SHIFT;
db_printf("%s", reg_name[rs1]);
db_printf("%s", fp_reg_name[rs1]);