+/* A capability is a combination of a FunTable and a RegTable. In STG
+ * code, BaseReg normally points to the RegTable portion of this
+ * structure, so that we can index both forwards and backwards to take
+ * advantage of shorter instruction forms on some archs (eg. x86).
+ * This is a cut-down version of the Capability structure; the full
+ * version is defined in Capability.h.
+ */
+struct PartCapability_ {
+ StgFunTable f;
+ StgRegTable r;
+};
+
+/* No such thing as a MainCapability under THREADED_RTS - each thread must have
+ * its own Capability.
+ */
+#if IN_STG_CODE && !defined(THREADED_RTS)
+extern W_ MainCapability[];
+#endif
+
+/*
+ * Assigning to BaseReg (the ASSIGN_BaseReg macro): this happens on
+ * return from a "safe" foreign call, when the thread might be running
+ * on a new Capability. Obviously if BaseReg is not a register, then
+ * we are restricted to a single Capability (this invariant is enforced
+ * in Capability.c:initCapabilities), and assigning to BaseReg can be omitted.
+ */
+
+#if defined(REG_Base) && !defined(NO_GLOBAL_REG_DECLS)