rites the load address */
if (argc > 2) {
hdr->ih_load = htonl(simple_strtoul(argv[2], NULL, 16));
}
break;
case IH_TYPE_KERNEL:
name = "Kernel Image";
break;
case IH_TYPE_MULTI:
name = "Multi-File Image";
len = ntohl(len_ptr[0]);
/* OS kernel is always the first image */
data += 8; /* kernel_len + terminator */
for (i=1; len_ptr[i]; ++i)
data += 4;
break;
default: printf ("Wrong Image Type for %s command\n", cmdtp->name);
SHOW_BOOT_PROGRESS (-5);
return 1;
}
SHOW_BOOT_PROGRESS (6);
/*
* We have reached the point of no return: we are going to
* overwrite all exception vector code, so we cannot easily
* recover from any failures any more...
*/
iflag = disable_interrupts();
#ifdef CONFIG_AMIGAONEG3SE
/*
* We've possible left the caches enabled during
* bios emulation, so turn them off again
*/
icache_disable();
invalidate_l1_instruction_cache();
flush_data_cache();
dcache_disable();
#endif
switch (hdr->ih_comp) { //根据镜像的压缩类型把内核镜像解压到指定的地址，一般是mkimage时-a指定的
那个地址，-a指定的那个地址也就是存储在镜像头里面的hdr->ih_load变量中，
什么时候指定的呢，其实就是在执行mkimage指令的时候，-a输入的时候，赋给的数值
case IH_COMP_NONE:
if(ntohl(hdr->ih_load) == addr) { //如果image header中指示的加载地址和bootm命令中参数2指定的地址相同，则表示不需要copy，可以就地执行。
printf (" XIP %s ... ", name);
} else {
#if defined(CONFIG_HW_WATCHDOG) || defined(CONFIG_WATCHDOG)
size_t l = len;
void *to = (void *)ntohl(hdr->ih_load);
void *from = (void *)data;
printf (" Loading %s ... ", name);
while (l > 0) {
size_t tail = (l > CHUNKSZ) CHUNKSZ : l;
WATCHDOG_RESET();
memmove (to, from, tail);
to += tail;
from += tail;
l -= tail;
}
#else /* !(CONFIG_HW_WATCHDOG || CONFIG_WATCHDOG) */如果image header中指示的加载地址和bootm命令中参数2指定的地址不相同，则表示要从image header中指示的加载地址处把image data copy到bootm命令中参数2指定的地址处，然后再执行。