* Patch by Scott McNutt, 21 Oct 2004:

[people/ms/u-boot.git] / cpu / nios2 / start.S

diff --git a/cpu/nios2/start.S b/cpu/nios2/start.S
index 281d42c2123c5a1de03095681ef82bb03d45e006..4c6e47066a3c770a7c1bc5ee26ee2627c1feddf8 100644 (file)
--- a/cpu/nios2/start.S
+++ b/cpu/nios2/start.S
@@ -39,14 +39,24 @@ _start:
         * just be invalidating the cache a second time. If cache
         * is not implemented initi behaves as nop.
         */
-       movhi   r4, %hi(CFG_ICACHELINE_SIZE)
-       ori     r4, r4, %lo(CFG_ICACHELINE_SIZE)
+       ori     r4, r0, %lo(CFG_ICACHELINE_SIZE)
        movhi   r5, %hi(CFG_ICACHE_SIZE)
        ori     r5, r5, %lo(CFG_ICACHE_SIZE)
        mov     r6, r0
 0:     initi   r6
        add     r6, r6, r4
        bltu    r6, r5, 0b
+       br      _except_end     /* Skip the tramp */
+
+       /* EXCEPTION TRAMPOLINE -- the following gets copied
+        * to the exception address (below), but is otherwise at the
+        * default exception vector offset (0x0020).
+        */
+_except_start:
+       movhi   et, %hi(_exception)
+       ori     et, et, %lo(_exception)
+       jmp     et
+_except_end:
 
        /* INTERRUPTS -- for now, all interrupts masked and globally
         * disabled.
@@ -117,7 +127,9 @@ _cur:       movhi   r5, %hi(_cur - _start)
 _reloc:
 
        /* COPY EXCEPTION TRAMPOLINE -- copy the tramp to the
-        * exception address.
+        * exception address. Define CONFIG_ROM_STUBS to prevent
+        * the copy (e.g. exception in flash or in other
+        * softare/firmware component).
         */
 #if !defined(CONFIG_ROM_STUBS)
        movhi   r4, %hi(_except_start)
@@ -126,12 +138,14 @@ _reloc:
        ori     r5, r5, %lo(_except_end)
        movhi   r6, %hi(CFG_EXCEPTION_ADDR)
        ori     r6, r6, %lo(CFG_EXCEPTION_ADDR)
+       beq     r4, r6, 7f      /* Skip if at proper addr */
 
 6:     ldwio   r7, 0(r4)
        stwio   r7, 0(r6)
        addi    r4, r4, 4
        addi    r6, r6, 4
        bne     r4, r5, 6b
+7:
 #endif
 
        /* STACK INIT -- zero top two words for call back chain.
@@ -155,15 +169,6 @@ _reloc:
         */
        br      _start
 
-       /* EXCEPTION TRAMPOLINE -- the following gets copied
-        * to the exception address.
-        */
-_except_start:
-       movhi   et, %hi(_exception)
-       ori     et, et, %lo(_exception)
-       jmp     et
-_except_end:
-
 
 /*
  * dly_clks -- Nios2 (like Nios1) doesn't have a timebase in