Changeset 8078180 in mainline

Timestamp:

2010-07-12T16:39:58Z (15 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

35599c9, 5f83634

Parents:

b539f54

Message:

Replace a branch instruction with conditional move.

File:

• kernel/arch/ia32/src/asm.S (modified) (1 diff)

kernel/arch/ia32/src/asm.S

@@ -412 +412 @@
          * Stop stack traces here if we came from userspace.
          */
+        xorl %eax, %eax
         cmpl $8, ISTATE_OFFSET_CS(%esp)
-        jz 0f
-        xorl %ebp, %ebp
-        
-        0:
-        
-                movl %ebp, ISTATE_OFFSET_EBP_FRAME(%esp)
-                movl ISTATE_OFFSET_EIP(%esp), %eax
-                movl %eax, ISTATE_OFFSET_EIP_FRAME(%esp)
-                leal ISTATE_OFFSET_EBP_FRAME(%esp), %ebp
-                
-                cld
-                
-                pushl %esp   /* pass istate address */
-                pushl $(\i)  /* pass intnum */
-                
-                /* Call exc_dispatch(intnum, istate) */
-                call exc_dispatch
-                
-                addl $8, %esp  /* clear arguments from the stack */
-                
-                /*
-                 * Restore the selector registers.
-                 */
-                movl ISTATE_OFFSET_GS(%esp), %ecx
-                movl ISTATE_OFFSET_FS(%esp), %edx
-
-                movl %ecx, %gs
-                movl %edx, %fs
-
-                movl ISTATE_OFFSET_ES(%esp), %ecx
-                movl ISTATE_OFFSET_DS(%esp), %edx
-                
-                movl %ecx, %es
-                movl %edx, %ds
-                
-                /*
-                 * Restore the scratch registers and the preserved
-                 * registers the handler cloberred itself
-                 * (i.e. EBP).
-                 */
-                movl ISTATE_OFFSET_EAX(%esp), %eax
-                movl ISTATE_OFFSET_ECX(%esp), %ecx
-                movl ISTATE_OFFSET_EDX(%esp), %edx
-                movl ISTATE_OFFSET_EBP(%esp), %ebp
-                
-                addl $(ISTATE_SOFT_SIZE + 4), %esp
-                iret
+        cmovl %eax, %ebp
+
+        movl %ebp, ISTATE_OFFSET_EBP_FRAME(%esp)
+        movl ISTATE_OFFSET_EIP(%esp), %eax
+        movl %eax, ISTATE_OFFSET_EIP_FRAME(%esp)
+        leal ISTATE_OFFSET_EBP_FRAME(%esp), %ebp
+                
+        cld
+                
+        pushl %esp   /* pass istate address */
+        pushl $(\i)  /* pass intnum */
+                
+        /* Call exc_dispatch(intnum, istate) */
+        call exc_dispatch
+                
+        addl $8, %esp  /* clear arguments from the stack */
+                
+        /*
+         * Restore the selector registers.
+         */
+        movl ISTATE_OFFSET_GS(%esp), %ecx
+        movl ISTATE_OFFSET_FS(%esp), %edx
+
+        movl %ecx, %gs
+        movl %edx, %fs
+
+        movl ISTATE_OFFSET_ES(%esp), %ecx
+        movl ISTATE_OFFSET_DS(%esp), %edx
+                
+        movl %ecx, %es
+        movl %edx, %ds
+                
+        /*
+         * Restore the scratch registers and the preserved
+         * registers the handler cloberred itself
+         * (i.e. EBP).
+         */
+        movl ISTATE_OFFSET_EAX(%esp), %eax
+        movl ISTATE_OFFSET_ECX(%esp), %ecx
+        movl ISTATE_OFFSET_EDX(%esp), %edx
+        movl ISTATE_OFFSET_EBP(%esp), %ebp
+                
+        addl $(ISTATE_SOFT_SIZE + 4), %esp
+        iret
 .endm