0.7.0–0.9.0 — Labels, Layout, and Near Jumps

This trio of versions is where Kasm stopped being a straight-line instruction emitter and started being able to describe programs with control flow.

0.7.0 — Labels that don’t cost bytes

8f4f3b3 — Update project version to 0.7.0, implement label definitions, and enhance Windows execution support parsed label definitions — including consecutive labels pointing at the same location — without emitting any bytes for them. A label is purely a name bound to a position; it has zero size in the encoded image.

0.8.0 — A layout pass, finally

Parsing labels is easy. Knowing where they point requires knowing the size of everything before them, which requires a dedicated pass. e643517 — Update project version to 0.8.0, implement layout functionality, and add label handling introduced that pass: it walks the statement array once, assigns byte offsets to instructions and labels, rejects duplicate label names, and provides an offset lookup used by everything that follows — jumps, relocations, and (much later) data directives and location-aware $/ $$ expressions.

Introducing a distinct layout stage — separate from parsing and separate from encoding — is arguably the single most consequential structural decision in Kasm’s history. Every forward-reference feature added after this point (near/short/absolute jumps, conditional branches, TIMES/FILL counts, $/$$) depends on layout running to completion before encoding starts.

0.9.0 — Near jumps and forward references

d98a002 — Update project version to 0.9.0, implement near jump functionality, and enhance parser and encoder added jmp with a signed relative displacement, resolved against the label table built during layout. This is the first feature that genuinely required the layout pass: a forward jump’s displacement can’t be computed until the size of every instruction between the jump and its target is known.

At this point Kasm could express loops and forward branches, but only in one jump form, and only as a raw relative displacement. The next chapter adds a second jump form, a relocation mechanism, and jumps through memory rather than through an immediate displacement.