diff options
| author | Grissiom <[email protected]> | 2013-11-17 12:13:25 +0800 |
|---|---|---|
| committer | Grissiom <[email protected]> | 2013-11-17 12:49:07 +0800 |
| commit | a8520ed383e9557993d647f477ecb4d6658c3ccd (patch) | |
| tree | 2e6ace23f4d3b4c217599689f5201a69cd8e2831 /libcpu | |
| parent | 394657979dcbac390d320cfbed57cacfbc631581 (diff) | |
cortex-r4: let svc mode reuse the stack of IRQ on startup
As the svc stack is the stack of threads, there is no need to allocate a
separate stack for the startup. Reuse the IRQ stack should be OK.
Tested on rm48 board.
Diffstat (limited to 'libcpu')
| -rw-r--r-- | libcpu/arm/cortex-r4/start_gcc.S | 18 |
1 files changed, 7 insertions, 11 deletions
diff --git a/libcpu/arm/cortex-r4/start_gcc.S b/libcpu/arm/cortex-r4/start_gcc.S index 20a1ccfc0f..3d679d0a22 100644 --- a/libcpu/arm/cortex-r4/start_gcc.S +++ b/libcpu/arm/cortex-r4/start_gcc.S @@ -18,11 +18,10 @@ .equ F_Bit, 0x40 @ when F bit is set, FIQ is disabled .equ UND_Stack_Size, 0x00000000 -.equ SVC_Stack_Size, 0x00000100 +.equ SVC_Stack_Size, 0x00000000 .equ ABT_Stack_Size, 0x00000000 -.equ FIQ_Stack_Size, 0x00000000 -.equ IRQ_Stack_Size, 0x00000100 -.equ USR_Stack_Size, 0x00000100 +.equ FIQ_Stack_Size, 0x00001000 +.equ IRQ_Stack_Size, 0x00001000 .section .bss.noinit /* stack */ @@ -63,6 +62,9 @@ _reset: @ Initialize Stack Pointers ldr r0, =stack_top + @ Set the startup stack for svc + mov sp, r0 + @ Enter Undefined Instruction Mode and set its Stack Pointer msr cpsr_c, #Mode_UND|I_Bit|F_Bit mov sp, r0 @@ -83,14 +85,8 @@ _reset: mov sp, r0 sub r0, r0, #IRQ_Stack_Size - @ Enter Supervisor Mode and set its Stack Pointer + @ Switch back to SVC msr cpsr_c, #Mode_SVC|I_Bit|F_Bit - mov sp, r0 - sub r0, r0, #SVC_Stack_Size - - @ Enter User Mode and set its Stack Pointer - mov sp, r0 - sub sl, sp, #USR_Stack_Size bl next1 next1: |