KOS_OP_PUSH_LOOP

• Style: NOARG. Argument unused; break target is derived at runtime from the extent table (pop_pc + 1). Continue target = instruction immediately following PUSH_LOOP (i.e. CURRENT_PC after the evaluator has advanced past the opcode).

• Stack: Pushes the LOOP node, which owns its segment. Break/continue use break_pc (derived at runtime) and continue_pc (next instruction after PUSH_LOOP). Initializes node result to None.

• Pushes: KOS_DYN_LOOP (static extent KOS_EXT_LOOP; with its own segment for the loop body).

• Invariants: A KOS_EXT_LOOP extent must exist at the PUSH_LOOP PC; otherwise RuntimeError. Extent kind KOS_EXT_LOOP.

• Compiler form: Pre-compile arg = 0 (unused). Break target is not stored in the instruction; it is derived at runtime via kos_extent_find(KOS_EXT_LOOP) → ext->pop_pc + 1.

Example: while loop. Break target derived from extent table (pop_pc+1 = 6).

index	opcode	arg	arg view	comment
0	PUSH_LOOP	0	0	push LOOP region; break_pc = pop_pc+1 from extent table; continue_pc = 1
1	CONST	0	0 (False)	condition
2	JUMP_FALSE	5	5 (-> 5)	exit loop if false; jumps to POP_LOOP
3	…	…	…	body
4	JUMP	1	1 (-> 1)	continue (loop head)
5	POP_LOOP	0	0
6	LABEL	–	–	break target (= pop_pc+1)