update 2

calling-convention/Output-explanation.md

@@ -30,3 +30,30 @@ Before the call, the 4 caller-saved registers (R0-R3) are pushed onto the
 stack to preserve their values. `RS` points to position 4, reflecting those
 4 entries. After `undo_function_call`, the stack is empty, `RS` returns to 0,
 and the result value `42` is successfully collected from `RA`.
+
+---
+
+## TEST 2: 8 arguments, some overflow to the stack
+
+**Function signature:** `result = func(a, b, c, d, e, f, g, h)`
+
+**Output**
+```
+===== TEST 2: 8 arguments, some on the stack =====
+=== State after do_function_call ===
+Registers used: ['RA', 'RB', 'RC', 'RD', 'R8', 'R9']
+Stack: [{'type': 'caller_saved', 'reg': 'R0', 'value': 0}, {'type': 'caller_saved', 'reg': 'R1', 'value': 0}, {'type': 'caller_saved', 'reg': 'R2', 'value': 0}, {'type': 'caller_saved', 'reg': 'R3', 'value': 0}, {'type': 'param', 'name': 'g', 'size': 64, 'value': 0}, {'type': 'param', 'name': 'h', 'size': 64, 'value': 0}]
+RS points to: 6
+=== State after undo_function_call ===
+Clean stack: []
+RS: 0
+Collected result: {'result': {'type': 'result', 'value': 99}}
+```
+
+**Explanation:**
+Spider provides 6 registers for passing arguments: RA, RB, RC, RD, R8, R9.
+The first 6 arguments (a through f) fill all available registers.
+Arguments `g` and `h`, which are 64-bit values, have no registers left and
+are pushed onto the stack instead. `RS` points to 6, reflecting the 4
+caller-saved entries plus 2 stack parameters. After `undo_function_call`,
+all stack entries are cleaned and the result `99` is collected from `RA`.