MIPS dynamic memory allocation using sbrk

Question

I was trying to use sbrk for dynamic memory allocation. But, being a newcomer to SPIM and MIPS, I was unable to do so. I sketched out a rough code for the same.

.data
    var: .word 25
.text   
    main:
        li $v0, 9
        la $v0, var
        lw $a0, var
        syscall     # DYNAMICALLY ALLOCATING MEMORY OF SIZE 4 BYTES AT ADDRESS OF VAR
        sw $v0, var
        
        li $v0, 10
        syscall

Exactly what errors are you getting? – NPE Mar 23 '14 at 09:29 — NPE, Mar 23 '14 at 09:29
`sbrk` is system call number 9, not 8. – Michael Mar 23 '14 at 09:39 — Michael, Mar 23 '14 at 09:39
The error is : UNKNOWN SYSTEM CALL – Sahil Babbar Mar 23 '14 at 10:04 — Sahil Babbar, Mar 23 '14 at 10:04

score 5 · Accepted Answer · edited Dec 02 '20 at 01:00

.data
    var: .word 25
.text   
    main:
        li $v0, 9
        lw $a0, var
        syscall     # DYNAMICALLY ALLOCATING MEMORY OF SIZE 4 BYTES AT ADDRESS OF VAR
        sw $v0, var
        
        li $v0, 10
        syscall

Only the second statement needs to be omitted as the system is waiting to get a amount of byte that should be allocated but above I was trying to give the address of var but this is result. The sbrk service returns the address to a block of memory containing n additional bytes. This would be used for dynamic memory allocation.

MIPS dynamic memory allocation using sbrk

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