Initializers are store runs
Writing fields is the mirror image of reading them: one store per field, each with that field's offset. Functions that set up a struct — constructors in spirit — compile to a tidy run of stores against one base register:
typedef struct {
s32 x; // offset 0
s32 y; // offset 4
} Point;
void move_to(Point *p, s32 nx, s32 ny) {
p->x = nx;
p->y = ny;
}
sw a1, 0(a0) # p->x = nx
sw a2, 4(a0) # p->y = ny
jr ra
nop
Nothing new mechanically — this is the out-parameter pattern from the pointers chapter with named offsets. The reading skill is the inventory: list every store's offset, map each to a field, and note what register it stores. Arguments map to parameters; zero maps to = 0; a scratch register means a computed value, so trace it upward.
One habit that pays off: when several consecutive fields get stored in one function, that function is probably an init or reset helper, and the field order in the stores usually tracks the declaration order. Seeing the shape ("this initializes a Gauge") gets you to the C faster than decoding line by line.
The target initializes all three fields of the Gauge below — read carefully which register lands where.
Your task
Write func_800ef3b4 to reproduce the target assembly.