MIPS Register

Abstract

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What is the purpose of register zero?

We can use it to assign the value of one variable to another, like add $s0, $s1, $zero, which is equivalent to $s0 = $s1.

Important

$v0 and $v1 are used by functions to return values.

$a0, $a1, $a2, and $a3 are used to pass arguments to functions.

$at is used by the assembler to store temporary values for pseudo-instructions.

$t0 through $t9 are not preserved across function calls. If a function calls another function, the values in $t0 through $t9 may be overwritten when the called function returns. We can push the values in $t0 through $t9 onto the stack before calling the function and restore the values back to the registers when the called function returns.

$s0 through $s7 are preserved across functions calls!

$v0 is same as $2!