thus the compiler cannot perform type checks on these assignments.
2. The pointer to the jump table is passed to the application in a
- machine-dependent way. PowerPC, ARM and MIPS architectures use a
- dedicated register to hold the pointer to the 'global_data'
- structure: r29 on PowerPC, r8 on ARM and k0 on MIPS. The x86
- architecture does not use such a register; instead, the pointer to
- the 'global_data' structure is passed as 'argv[-1]' pointer.
+ machine-dependent way. PowerPC, ARM, MIPS, Blackfin and Nios II
+ architectures use a dedicated register to hold the pointer to the
+ 'global_data' structure: r2 on PowerPC, r8 on ARM, k0 on MIPS,
+ P3 on Blackfin and gp on Nios II. The x86 architecture does not
+ use such a register; instead, the pointer to the 'global_data'
+ structure is passed as 'argv[-1]' pointer.
The application can access the 'global_data' structure in the same
way as U-Boot does:
that returns the ABI version of the running U-Boot. I.e., a
typical application startup may look like this:
- int my_app (int argc, char *argv[])
+ int my_app (int argc, char * const argv[])
{
app_startup (argv);
if (get_version () != XF_VERSION)
4. The default load and start addresses of the applications are as
follows:
- Load address Start address
- x86 0x00040000 0x00040000
- PowerPC 0x00040000 0x00040004
- ARM 0x0c100000 0x0c100000
- MIPS 0x80200000 0x80200000
+ Load address Start address
+ x86 0x00040000 0x00040000
+ PowerPC 0x00040000 0x00040004
+ ARM 0x0c100000 0x0c100000
+ MIPS 0x80200000 0x80200000
+ Blackfin 0x00001000 0x00001000
+ NDS32 0x00300000 0x00300000
+ Nios II 0x02000000 0x02000000
For example, the "hello world" application may be loaded and
executed on a PowerPC board with the following commands: