数组如何存储在寄存器文件中？

Question

I am looking at a 32x32 register file, with $s0-$s7, $t0-$t9, $zero, $a0-$a3, $v0-$v1, $gp, $fp, $ra, and $at.

My question is how is an array stored in these register files? Aren't they only each 32-bits wide?

For example, given base address of an array A is $s3, if I were to give instruction to get A[8]:

lw $t0, 32($s3)

How does it retrieve the data?

Answer 1

Array access is made through pointer (something the C people are very familiar with), so the register simply holds the base address of the array. You are then adding 8 * 4 = 32 bytes to that base address to get the address of the 8th element and finally dereferencing that pointer (which means seeing what's at that address) to get the value (with the lw instruction).

The instruction you have shown is the translation of this C code:

t0 = *(s3 + 8)  // same as s3[8]