KOS_OP_OBJECT_COMPARE

• Style: CMPCOUNT. Arg packs a KosCompare selector (high byte) with the reducing count (low byte).

• Stack: [..., a1, ..., aN] → [..., result]. Chain-compare N stack values under the selector and push the result (N >= 2; raises TypeError otherwise).

• Semantics: The richcompare six (LT/LE/EQ/NE/GT/GE, ordinals 0-5, matching CPython’s Py_LT..Py_GE) chain left-to-right and push the last richcompare result. The extended selectors push a bool. IS / IS_NOT / IN / NOT_IN are strictly binary. IS_INSTANCE / IS_SUBCLASS test the first operand against each operand after it and hold on the first match; a tuple operand is opened one level and each item tested, and a tuple inside it raises TypeError.

• Compiler form: Emitted by the comparison, predicate, and type-check specials with a (selector, count) pair, merged to the packed uint16 at normalize. When immediately followed by JUMP_FALSE, compress fuses the pair into CHECK_COMPARE.

Example: (instance? x int float) – value plus two types. The literal (instance? x #(int float)) compiles to the same instructions, the tuple spliced at compile time.

index	opcode	arg	arg view	comment
0	FAST	0	0 (x)	stack: […, x]
1	FAST	1	1 (int)	stack: […, x, int]
2	FAST	2	2 (float)	stack: […, x, int, float]
3	OBJECT_COMPARE	2563	(IS_INSTANCE x3)	stack: […, bool]