The variable whose name went missing
A file-scope static is compiled exactly like any other global: it lives in .data or .bss, its address goes into the literal pool, and the reads and writes are the same two-step dance. Nothing about static changes the code the compiler emits.
One thing does change in the listing. The assembler plants an ARM mapping symbol called $d at offset 0 of each data region, marking "data starts here". When a local symbol happens to sit at that same offset, the workspace resolves the relocation to $d and the variable's own name disappears:
0 ldr r2, [pc, #12] (->16)
2 ldr r1, [pc, #16] (->20)
4 ldr r0, [r2, #0]
6 ldr r1, [r1, #0]
8 add r0, r1
10 str r0, [r2, #0]
12 bx lr
14 .hword 0
16 .word sMasterVol
20 .word $d
volUp adds a step static into a master-volume static and stores the result back. Both are static s32 with initialisers, so both live in .data in declaration order. sMasterVol was declared second, sits four bytes in, and keeps its name; the static declared ahead of it landed at offset 0 and shows up as $d.
So $d in a pool row means "a file-local object, and I am not going to tell you which one". That is a fair simulation of real decompilation work, where the symbol table of a retail ROM has no names for anything. You recover the identity from behaviour: what gets written to it, what it is compared against, which other rows in the function share it.
Which static gets the $d treatment depends on declaration order, and only one per section can. Whichever names do survive are a strong clue to what the nameless one must be.
Your target works on two statics, one of each kind, and touches one of them three times.
Your task
Write func_0833faf4 to reproduce the target assembly.