* sparc-tdep.c (sparc_get_saved_register): Comment why

get_prev_frame call is safe.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index c7e3758..2147937 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,10 @@
 2002-05-04  Andrew Cagney  <ac131313@redhat.com>
 
+       * sparc-tdep.c (sparc_get_saved_register): Comment why
+       get_prev_frame call is safe.
+
+2002-05-04  Andrew Cagney  <ac131313@redhat.com>
+
        * frame.h (select_frame): Delete level parameter.
        * stack.c (select_frame): Update.  Use frame_relative_level to
        obtain the frame's level.

diff --git a/gdb/sparc-tdep.c b/gdb/sparc-tdep.c
index 28c51dc..6461ca0 100644 (file)
--- a/gdb/sparc-tdep.c
+++ b/gdb/sparc-tdep.c
@@ -855,10 +855,20 @@ sparc_get_saved_register (char *raw_buffer, int *optimized, CORE_ADDR *addrp,
            addr = frame1->frame + (regnum - G0_REGNUM) * SPARC_INTREG_SIZE
              - (FP_REGISTER_BYTES + 8 * SPARC_INTREG_SIZE);
          else if (regnum >= I0_REGNUM && regnum < I0_REGNUM + 8)
+           /* NOTE: cagney/2002-05-04: The call to get_prev_frame()
+               is safe/cheap - there will always be a prev frame.
+               This is because frame1 is initialized to frame->next
+               (frame1->prev == frame) and is then advanced towards
+               the innermost (next) frame.  */
            addr = (get_prev_frame (frame1)->extra_info->bottom
                    + (regnum - I0_REGNUM) * SPARC_INTREG_SIZE
                    + FRAME_SAVED_I0);
          else if (regnum >= L0_REGNUM && regnum < L0_REGNUM + 8)
+           /* NOTE: cagney/2002-05-04: The call to get_prev_frame()
+               is safe/cheap - there will always be a prev frame.
+               This is because frame1 is initialized to frame->next
+               (frame1->prev == frame) and is then advanced towards
+               the innermost (next) frame.  */
            addr = (get_prev_frame (frame1)->extra_info->bottom
                    + (regnum - L0_REGNUM) * SPARC_INTREG_SIZE
                    + FRAME_SAVED_L0);