1 %default {"preinstr":"", "result":"a0", "chkzero":"0"} 2 /* 3 * Generic 32-bit "lit8" binary operation. Provide an "instr" line 4 * that specifies an instruction that performs "result = a0 op a1". 5 * This could be an MIPS instruction or a function call. (If the result 6 * comes back in a register other than a0, you can override "result".) 7 * 8 * If "chkzero" is set to 1, we perform a divide-by-zero check on 9 * CC (a1). Useful for integer division and modulus. 10 * 11 * For: add-int/lit8, rsub-int/lit8, mul-int/lit8, div-int/lit8, 12 * rem-int/lit8, and-int/lit8, or-int/lit8, xor-int/lit8, 13 * shl-int/lit8, shr-int/lit8, ushr-int/lit8 14 */ 15 /* binop/lit8 vAA, vBB, #+CC */ 16 lbu a3, 2(rPC) # a3 <- BB 17 lb a1, 3(rPC) # a1 <- sign-extended CC 18 srl a2, rINST, 8 # a2 <- AA 19 GET_VREG a0, a3 # a0 <- vBB 20 .if $chkzero 21 beqz a1, common_errDivideByZero # is second operand zero? 22 .endif 23 FETCH_ADVANCE_INST 2 # advance rPC, load rINST 24 $preinstr # optional op 25 $instr # $result <- op, a0-a3 changed 26 GET_INST_OPCODE v0 # extract opcode from rINST 27 SET_VREG $result, a2 # vAA <- $result 28 GOTO_OPCODE v0 # jump to next instruction 29 30
