Add brl long branch ($82) to the assembler - #90
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The disassembler already knew $82; the opcode table lacked it, forcing jmp.w for long intra-routine jumps. brl stays PC-relative (16-bit signed, +/-32K), so it never touches the symbol table.
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Why
brl($82) — the 65816's unconditional 16-bit PC-relative branch (±32 KB) — was assemble-unsupported. The disassembler already decoded it (0x82: ("brl", RELATIVE_LONG, 2)), but the opcode table had no entry, so you could readbrlbut not write it.The consequence: a long intra-routine back-edge (loop body > 127 bytes, past
brarange) had to usejmp.w <local>— absolute, deferred to the linker, touching the symbol table. That's the exact path behind the recently-fixed local-label collisions (#88, #89).brlis the correct primitive: PC-relative, resolved in-section at assemble time, layout-invariant, never consults a symbol — immune to that whole class.Closes the "natural fix" the jmp.w-local report flagged.
What
RelativeJumpOpcodeparametrized by offset width (OFFSET_BYTES); displacement =dest - pc - (1 + OFFSET_BYTES). Existing 8-bit branches unchanged.RelativeLongJumpOpcode(2-byte signed offset, range ±32767) →brl=$82.Test plan
brl <backward label>/<forward label>encode82 lo hiwith the correct signed-16 displacement, both directions.bra/bcc/…) still encode identically (shared, re-parametrized path).