#define CONTEXT_ADDR_FROM_STEM(stem) &context->uc_mcontext.mc_ ## stem
#elif defined __OpenBSD__
#define CONTEXT_ADDR_FROM_STEM(stem) &context->sc_ ## stem
+#elif defined __NetBSD__
+#define CONTEXT_ADDR_FROM_STEM(stem) &((context)->uc_mcontext.__gregs[_REG_ ## stem])
#else
#error unsupported BSD variant
#endif