X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?p=pintos-anon;a=blobdiff_plain;f=src%2Fthreads%2Finterrupt.h;fp=src%2Fthreads%2Finterrupt.h;h=b805671e626d6891f1b43aa06de64674f15a91d6;hp=99abf8e3a92ddecff94064dd7bbaf5f0086e774d;hb=251b51f76f0594460e1cfbf2c05576fb445b861b;hpb=c9613f4d1fd208911409de6f82b430e5f9a595ae

diff --git a/src/threads/interrupt.h b/src/threads/interrupt.h
index 99abf8e..b805671 100644
--- a/src/threads/interrupt.h
+++ b/src/threads/interrupt.h
@@ -19,7 +19,7 @@ enum intr_level intr_disable (void);
 /* Interrupt stack frame. */
 struct intr_frame
   {
-    /* Pushed by intr_entry in intr-stubs.S (see intr-stubs.pl).
+    /* Pushed by intr_entry in intr-stubs.S.
        These are the interrupted task's saved registers. */
     uint32_t edi;               /* Saved EDI. */
     uint32_t esi;               /* Saved ESI. */
@@ -34,13 +34,18 @@ struct intr_frame
     uint16_t es, :16;           /* Saved ES segment register. */
     uint16_t ds, :16;           /* Saved DS segment register. */
 
-    /* Pushed by intrXX_stub in intr-stubs.S (see intr-stubs.pl). */
+    /* Pushed by intrNN_stub in intr-stubs.S. */
     uint32_t vec_no;            /* Interrupt vector number. */
 
     /* Sometimes pushed by the CPU,
-       otherwise for consistency pushed as 0 by intrXX_stub. */
+       otherwise for consistency pushed as 0 by intrNN_stub.
+       The CPU puts it just under `eip', but we move it here. */
     uint32_t error_code;        /* Error code. */
 
+    /* Pushed by intrNN_stub in intr-stubs.S.
+       This frame pointer eases interpretation of backtraces. */
+    void *frame_pointer;        /* Saved EBP (frame pointer). */
+
     /* Pushed by the CPU.
        These are the interrupted task's saved registers. */
     void (*eip) (void);         /* Next instruction to execute. */