From 63d7a4f12e71aae081676e4d15b615cc9709289c Mon Sep 17 00:00:00 2001
From: Jim Blandy <jimb@codesourcery.com>
Date: Mon, 7 Dec 1998 20:28:54 +0000
Subject: [PATCH] * rs6000-tdep.c (pop_frame): Correctly find the registers
 saved in the stack frame.  Their offset from the previous stack frame is in
 fdata.gpr_offset and fdata.fpr_offset, not fdata.offset.
 (gdb.base/return.exp) * config/rs6000/tm-rs6000.h: Doc fixes.

---
 gdb/config/rs6000/tm-rs6000.h | 10 ++++++----
 gdb/rs6000-tdep.c             | 32 +++++++++++++++++++-------------
 2 files changed, 25 insertions(+), 17 deletions(-)

diff --git a/gdb/config/rs6000/tm-rs6000.h b/gdb/config/rs6000/tm-rs6000.h
index 339d8a8c13..0ea9bf604b 100644
--- a/gdb/config/rs6000/tm-rs6000.h
+++ b/gdb/config/rs6000/tm-rs6000.h
@@ -66,14 +66,16 @@ struct fp_status {
 /* To be used by skip_prologue. */
 
 struct rs6000_framedata {
-  int	offset;				/* # of bytes in gpr's and fpr's are saved */
+  int	offset;				/* total size of frame --- the distance
+					   by which we decrement sp to allocate
+					   the frame */
   int	saved_gpr;			/* smallest # of saved gpr */
   int	saved_fpr;			/* smallest # of saved fpr */
   int	alloca_reg;			/* alloca register number (frame ptr) */
   char	frameless;			/* true if frameless functions. */
   char	nosavedpc;			/* true if pc not saved. */
-  int	gpr_offset;			/* offset of saved gprs */
-  int	fpr_offset;			/* offset of saved fprs */
+  int	gpr_offset;			/* offset of saved gprs from prev sp */
+  int	fpr_offset;			/* offset of saved fprs from prev sp */
   int	lr_offset;			/* offset of saved lr */
   int	cr_offset;			/* offset of saved cr */
 };
@@ -149,7 +151,7 @@ extern void aix_process_linenos PARAMS ((void));
 
 /* Stack grows downward.  */
 
-#define INNER_THAN <
+#define INNER_THAN(lhs,rhs) ((lhs) < (rhs))
 
 /* This is how arguments pushed onto stack or passed in registers.
    Stack must be aligned on 64-bit boundaries when synthesizing
diff --git a/gdb/rs6000-tdep.c b/gdb/rs6000-tdep.c
index 47fd886dc2..e25ffdf9df 100644
--- a/gdb/rs6000-tdep.c
+++ b/gdb/rs6000-tdep.c
@@ -213,19 +213,20 @@ rs6000_software_single_step (signal, insert_breakpoints_p)
 /* return pc value after skipping a function prologue and also return
    information about a function frame.
 
-   in struct rs6000_frameinfo fdata:
+   in struct rs6000_framedata fdata:
     - frameless is TRUE, if function does not have a frame.
     - nosavedpc is TRUE, if function does not save %pc value in its frame.
-    - offset is the number of bytes used in the frame to save registers.
+    - offset is the initial size of this stack frame --- the amount by
+      which we decrement the sp to allocate the frame.
     - saved_gpr is the number of the first saved gpr.
     - saved_fpr is the number of the first saved fpr.
     - alloca_reg is the number of the register used for alloca() handling.
       Otherwise -1.
-    - gpr_offset is the offset of the saved gprs
-    - fpr_offset is the offset of the saved fprs
+    - gpr_offset is the offset of the first saved gpr from the previous frame.
+    - fpr_offset is the offset of the first saved fpr from the previous frame.
     - lr_offset is the offset of the saved lr
     - cr_offset is the offset of the saved cr
- */
+*/
 
 #define SIGNED_SHORT(x) 						\
   ((sizeof (short) == 2)						\
@@ -668,19 +669,24 @@ pop_frame ()
   write_register (PC_REGNUM, lr);
 
   /* reset register values if any was saved earlier. */
-  addr = prev_sp - fdata.offset;
 
   if (fdata.saved_gpr != -1)
-    for (ii = fdata.saved_gpr; ii <= 31; ++ii) {
-      read_memory (addr, &registers [REGISTER_BYTE (ii)], 4);
-      addr += 4;
+    {
+      addr = prev_sp + fdata.gpr_offset;
+      for (ii = fdata.saved_gpr; ii <= 31; ++ii) {
+	read_memory (addr, &registers [REGISTER_BYTE (ii)], 4);
+	addr += 4;
+      }
     }
 
   if (fdata.saved_fpr != -1)
-    for (ii = fdata.saved_fpr; ii <= 31; ++ii) {
-      read_memory (addr, &registers [REGISTER_BYTE (ii+FP0_REGNUM)], 8);
-      addr += 8;
-  }
+    {
+      addr = prev_sp + fdata.fpr_offset;
+      for (ii = fdata.saved_fpr; ii <= 31; ++ii) {
+	read_memory (addr, &registers [REGISTER_BYTE (ii+FP0_REGNUM)], 8);
+	addr += 8;
+      }
+    }
 
   write_register (SP_REGNUM, prev_sp);
   target_store_registers (-1);