1 %default {"preinstr":"", "result":"a0", "chkzero":"0"} 2 /* 3 * Generic 32-bit "/2addr" binary operation. Provide an "instr" line 4 * that specifies an instruction that performs "result = a0 op a1". 5 * This could be a 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 * vB (a1). Useful for integer division and modulus. Note that we 10 * *don't* check for (INT_MIN / -1) here, because the CPU handles it 11 * correctly. 12 * 13 * For: add-int/2addr, sub-int/2addr, mul-int/2addr, div-int/2addr, 14 * rem-int/2addr, and-int/2addr, or-int/2addr, xor-int/2addr, 15 * shl-int/2addr, shr-int/2addr, ushr-int/2addr 16 */ 17 /* binop/2addr vA, vB */ 18 ext a2, rINST, 8, 4 # a2 <- A 19 ext a3, rINST, 12, 4 # a3 <- B 20 GET_VREG a0, a2 # a0 <- vA 21 GET_VREG a1, a3 # a1 <- vB 22 .if $chkzero 23 beqz a1, common_errDivideByZero # is second operand zero? 24 .endif 25 FETCH_ADVANCE_INST 1 # advance rPC, load rINST 26 $preinstr # optional op 27 $instr # $result <- op, a0-a3 changed 28 GET_INST_OPCODE v0 # extract opcode from rINST 29 SET_VREG $result, a2 # vA <- $result 30 GOTO_OPCODE v0 # jump to next instruction 31
