mambo: Fix bt command and add little endian support

This fixes the bt (back trace) command which had bit rot.

It also adds little endian support.

Format looks like this:
  systemsim % bt
  pc:                             0x000000003007F270
  lr:                             0x000000003007EFAC
  stack:0x0000000031C03B60        0x0000000031C03BF0
  stack:0x0000000031C03C00        0x0000000030022F44
  stack:0x0000000031C03C90        0x0000000030023000
  stack:0x0000000031C03D20        0x0000000030039540
  stack:0x0000000031C03E30        0x00000000300145BC
  stack:0x0000000031C03F00        0x000000003000259C

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>

1 files changed, 32 insertions, 8 deletions

diff --git a/external/mambo/mambo_utils.tcl b/external/mambo/mambo_utils.tcl
index 65bf036..cf156df 100644
--- a/external/mambo/mambo_utils.tcl
+++ b/external/mambo/mambo_utils.tcl
@@ -219,27 +219,51 @@ proc egdb { {t 0} } {
     gdb $t
 }
 
+proc mem_display_64_le { addr } {
+    set data 0
+    for {set i 0} {$i < 8} {incr i} {
+	set data [ expr $data << 8 ]
+	set l [ mysim memory display [ expr $addr+7-$i ] 1 ]
+	set data [ expr $data | $l ]
+    }
+    return [format 0x%X $data]
+}
+
+proc mem_display_64 { addr le } {
+    if { $le } {
+	return [ mem_display_64_le $addr ]
+    }
+    # mysim memory display is big endian
+    return [ mysim memory display $addr 8 ]
+}
+
 proc bt { {sp 0} } {
     set t 0
     if { $sp < 16 } {
         set t $sp
         set sp 0
     }
+    set lr [mysim cpu 0:$t display spr pc]
+    puts "pc:\t\t\t\t$lr"
     if { $sp == 0 } {
         set sp [mysim cpu 0:$t display gpr 1]
     }
     set lr [mysim cpu 0:$t display spr lr]
-    puts "backtrace thread $t, stack $sp"
-    i $lr
-    while { 1 == 1 } {
+    puts "lr:\t\t\t\t$lr"
+
+    set msr [mysim cpu 0:$t display spr msr]
+    set le [ expr $msr & 1 ]
+
+    # Limit to 200 in case of an infinite loop
+    for {set i 0} {$i < 200} {incr i} {
         set pa [ mysim util dtranslate $sp ]
-        set bc [ mysim memory display $pa 8 ]
-        set cr [ mysim memory display [expr $pa+8] 8 ]
-        set lr [ mysim memory display [expr $pa+16] 8 ]
-        i $lr
-        if { $bc == 0 } { return }
+        set bc [ mem_display_64 $pa $le ]
+        set lr [ mem_display_64 [ expr $pa + 16 ] $le ]
+        puts "stack:$pa \t$lr"
+        if { $bc == 0 } { break }
         set sp $bc
     }
+    puts ""
 }
 
 proc ton { } {mysim mode turbo }