phase12: match func_800AC648 (708 bodies / 717 regions)

config/regions.tsv

@@ -513,6 +513,7 @@
 0x800AA56C	0x800AA59C	src/func_800AA56C.c
 0x800AB078	0x800AB0EC	src/func_800AB078.c
 0x800AB504	0x800AB598	src/func_800AB504.c	cc1=-fno-strength-reduce
+0x800AC648	0x800AC694	src/func_800AC648.c
 0x800AC818	0x800AC85C	src/func_800AC818.c
 0x800AC85C	0x800AC884	src/func_800AC85C.c
 0x800AC98C	0x800AC9D8	src/func_800AC98C.c

src/func_800AC648.c

@@ -0,0 +1,41 @@
+/*
+ * func_800AC648 — 76 bytes at 0x800AC648..0x800AC694
+ *
+ * Calls func_800ABA28 with the incoming pointer, saves the current stack pointer,
+ * switches to the alternate scratchpad stack at 0x1F8003DC, calls func_800BBDF8
+ * with the same pointer, and restores the original stack pointer.
+ *
+ * The three inline-assembly macros are the repository's sanctioned scratchpad-stack
+ * idiom: they are required because C cannot express reassignment of the machine
+ * stack pointer while preserving the compiler's own stack bookkeeping. The s0
+ * binding keeps the argument live across the stack switch and reproduces the target's
+ * save/restore and epilogue.
+ *
+ * LIMITS: the two callees and pointer meaning are not inferred. The scratchpad save
+ * slot 0x1F8003FC, alternate stack 0x1F8003DC, call order, argument preservation,
+ * frame, and restore sequence are byte evidence.
+ */
+
+#define SF3_SAVE_SP() \
+    __asm__ __volatile__("lui $at,0x1f80\n\t" \
+                         "sw $sp,1020($at)")
+#define SF3_SET_SP() \
+    __asm__ __volatile__("lui $sp,0x1f80\n\t" \
+                         "ori $sp,$sp,0x3dc")
+#define SF3_REST_SP() \
+    __asm__ __volatile__("lui $sp,0x1f80\n\t" \
+                         "lw $sp,1020($sp)")
+
+extern void func_800ABA28(int *);
+extern void func_800BBDF8(int *);
+
+void func_800AC648(int *a0)
+{
+    register int *s0 __asm__("$16") = a0;
+
+    func_800ABA28(s0);
+    SF3_SAVE_SP();
+    SF3_SET_SP();
+    func_800BBDF8(s0);
+    SF3_REST_SP();
+}