u-boot-brain/examples/stubs.c
wdenk 4a5517094d * Patch by Scott McNutt, 04 Oct 2003:
- add support for Altera Nios-32 CPU
  - add support for Nios Cyclone Development Kit (DK-1C20)

* Patch by Steven Scholz, 29 Sep 2003:
  - A second parameter for bootm overwrites the load address for
    "Standalone Application" images.
  - bootm sets environment variable "filesize" to the resulting
    (uncompressed) data length for "Standalone Application" images
    when autostart is set to "no". Now you can do something like
       if bootm $fpgadata $some_free_ram ; then
               fpga load 0 $some_free_ram $filesize
       fi

* Patch by Denis Peter, 25 Sept 2003:
  add support for the MIP405 Rev. C board
2003-10-08 23:26:14 +00:00

107 lines
2.9 KiB
C

#include <exports.h>
#if defined(CONFIG_I386)
/*
* x86 does not have a dedicated register to store the pointer to
* the global_data. Thus the jump table address is stored in a
* global variable, but such approach does not allow for execution
* from flash memory. The global_data address is passed as argv[-1]
* to the application program.
*/
static void **jt;
gd_t *global_data;
#define EXPORT_FUNC(x) \
asm volatile ( \
" .globl " #x "\n" \
#x ":\n" \
" movl %0, %%eax\n" \
" movl jt, %%ecx\n" \
" jmp *(%%ecx, %%eax)\n" \
: : "i"(XF_ ## x * sizeof(void *)) : "eax", "ecx");
#elif defined(CONFIG_PPC)
/*
* r29 holds the pointer to the global_data, r11 is a call-clobbered
* register
*/
#define EXPORT_FUNC(x) \
asm volatile ( \
" .globl " #x "\n" \
#x ":\n" \
" lwz %%r11, %0(%%r29)\n" \
" lwz %%r11, %1(%%r11)\n" \
" mtctr %%r11\n" \
" bctr\n" \
: : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "r11");
#elif defined(CONFIG_ARM)
/*
* r8 holds the pointer to the global_data, ip is a call-clobbered
* register
*/
#define EXPORT_FUNC(x) \
asm volatile ( \
" .globl " #x "\n" \
#x ":\n" \
" ldr ip, [r8, %0]\n" \
" ldr pc, [ip, %1]\n" \
: : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "ip");
#elif defined(CONFIG_MIPS)
/*
* k0 ($26) holds the pointer to the global_data; t9 ($25) is a call-
* clobbered register that is also used to set gp ($26). Note that the
* jr instruction also executes the instruction immediately following
* it; however, GCC/mips generates an additional `nop' after each asm
* statement
*/
#define EXPORT_FUNC(x) \
asm volatile ( \
" .globl " #x "\n" \
#x ":\n" \
" lw $25, %0($26)\n" \
" lw $25, %1($25)\n" \
" jr $25\n" \
: : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "t9");
#elif defined(CONFIG_NIOS)
/*
* %g7 holds the pointer to the global_data. %g0 is call clobbered.
*/
#define EXPORT_FUNC(x) \
asm volatile ( \
" .globl " #x "\n" \
#x ":\n" \
" pfx %%hi(%0)\n" \
" movi %%g0, %%lo(%0)\n" \
" add %%g0, %%g7\n" \
" ld %%g0, [%%g0]\n" \
" pfx %1\n" \
" ld %%g0, [%%g0]\n" \
" jmp %%g0\n" \
" nop \n" \
: : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x) : "r0");
#else
#error stubs definition missing for this architecture
#endif
/* This function is necessary to prevent the compiler from
* generating prologue/epilogue, preparing stack frame etc.
* The stub functions are special, they do not use the stack
* frame passed to them, but pass it intact to the actual
* implementation. On the other hand, asm() statements with
* arguments can be used only inside the functions (gcc limitation)
*/
static void __attribute__((unused)) dummy(void)
{
#include <_exports.h>
}
void app_startup(char **argv)
{
#if defined(CONFIG_I386)
/* x86 does not have a dedicated register for passing global_data */
global_data = (gd_t *)argv[-1];
jt = global_data->jt;
#endif
}
#undef EXPORT_FUNC