It sounds to as if the problem is that the 'Chromium' cross-compiler/assembler allows only structured control flow -- IOW, it will accept IF, ELSE, ENDIF, in the source code but not BNE BEQ and so on.

I have dealt with a similar situation when using Bill Ragsdale's RPN assembler for 6502. It sometimes happen that I want to use conditionals in an unstructured way, and I accomplish this by adding snippets in the source code, snippets which cause the necessary bytes to output. For example, ...
D0 C, DESIRED_DESTINATION HERE 1+ - C,
... will cause a BNE opcode then its 8-bit offset to be assembled.

This is somewhat messy, but it lets me "break the rules" and bypass the compiler security checking which otherwise insists that IF pair with ENDIF and so on... and the code Phillip is trying to reproduce breaks the rules in the same way.

If you search on this forum for "compiler security" then you'll find there's another (arguably less messy) way, and that involves juggling items the assembler has on stack instead. Here is one post in that vein.

That looks like source for a metacompiler's assembler.

I don't see a bias against labels

My Forth assembler, which also uses structured control flow, has BRAN, .

Yes, I saw that on the earlier thread, you've obviously honed this a bit, your RPN Forth assembly source code actually looks quite good, albeit not quite a simple IF, THEN, ELSE, in construction, but generally easy on the eye. If I do decide to build out the CamelForth assembler a bit more, I'll certainly come back to it.