diff options
Diffstat (limited to 'cpu/nios2/start.S')
| -rw-r--r-- | cpu/nios2/start.S | 29 |
1 files changed, 17 insertions, 12 deletions
diff --git a/cpu/nios2/start.S b/cpu/nios2/start.S index 281d42c..4c6e470 100644 --- 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 |