gdbstub: add helper for 128 bit registers

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20200316172155.971-11-alex.bennee@linaro.org>

include/exec/gdbstub.h

@@ -102,6 +102,19 @@ static inline int gdb_get_reg64(uint8_t *mem_buf, uint64_t val)
     return 8;
 }
 
+static inline int gdb_get_reg128(uint8_t *mem_buf, uint64_t val_hi,
+                                 uint64_t val_lo)
+{
+#ifdef TARGET_WORDS_BIGENDIAN
+    stq_p(mem_buf, val_hi);
+    stq_p(mem_buf + 8, val_lo);
+#else
+    stq_p(mem_buf, val_lo);
+    stq_p(mem_buf + 8, val_hi);
+#endif
+    return 16;
+}
+
 #if TARGET_LONG_BITS == 64
 #define gdb_get_regl(buf, val) gdb_get_reg64(buf, val)
 #define ldtul_p(addr) ldq_p(addr)