add
Add with overflow trap
Adds $t2 and $t3, or $t2 and an immediate, into $t1 and traps if the signed result overflows.
Used in
- The 32 registers and their namesMIPS assembly
- The MIPS instruction setMIPS assembly
- Loads, stores and immediatesMIPS assembly
- LoopsMIPS assembly
- Arithmetic, logic and bitsMIPS assembly
- Arrays and stringsMIPS assembly
- The stack and $spMIPS assembly
- jal, jr, and the course calling conventionMIPS assembly
- syscall in the PlaygroundMIPS assembly
- The bitmap display and keyboard registersMIPS assembly
Forms
add , ,
Pseudo-instructions
The assembler turns these into one or more real instructions.
Operands
$t1- Any general-purpose register,
$0to$31, using its numeric or named spelling, such as$8or$t0($zerois$0;$rais$31). $t2- A general-purpose register. It may be the same register as
$t1. $t3- A general-purpose register. It may be the same register as
$t1. imm- An immediate value: a signed 16-bit value (
-32768to32767) or a 32-bit value (-2147483648to4294967295). The assembler chooses a supported encoding for the value and other operands; a pseudoinstruction may expand into several instructions.
Raises an overflow exception if the true result does not fit in 32 bits. Use 'addu' when overflow should be silently ignored.
# Add two initialized values. Inspect $t2: it should contain 12.
li $t0, 7
li $t1, 5
add $t2, $t0, $t1
# Optional overflow variation: uncomment these lines before the normal completion point.
# li $t0, 0x7FFFFFFF
# li $t1, 1
# add $t2, $t0, $t1
# Expected: signed integer overflow stops execution.