| %def binopLit8(preinstr="", result="a0", chkzero="0", instr=""): | |
| /* | |
| * Generic 32-bit "lit8" binary operation. Provide an "instr" line | |
| * that specifies an instruction that performs "result = a0 op a1". | |
| * This could be an MIPS instruction or a function call. (If the result | |
| * comes back in a register other than a0, you can override "result".) | |
| * | |
| * If "chkzero" is set to 1, we perform a divide-by-zero check on | |
| * CC (a1). Useful for integer division and modulus. | |
| * | |
| * For: add-int/lit8, rsub-int/lit8, mul-int/lit8, div-int/lit8, | |
| * rem-int/lit8, and-int/lit8, or-int/lit8, xor-int/lit8, | |
| * shl-int/lit8, shr-int/lit8, ushr-int/lit8 | |
| */ | |
| /* binop/lit8 vAA, vBB, #+CC */ | |
| lbu a3, 2(rPC) # a3 <- BB | |
| lb a1, 3(rPC) # a1 <- sign-extended CC | |
| srl a2, rINST, 8 # a2 <- AA | |
| GET_VREG a0, a3 # a0 <- vBB | |
| .if $chkzero | |
| beqz a1, common_errDivideByZero # is second operand zero? | |
| .endif | |
| FETCH_ADVANCE_INST 2 # advance rPC, load rINST | |
| $preinstr # optional op | |
| $instr # $result <- op, a0-a3 changed | |
| GET_INST_OPCODE v0 # extract opcode from rINST | |
| SET_VREG $result, a2 # vAA <- $result | |
| GOTO_OPCODE v0 # jump to next instruction | |