我的硬件平台是S3C2410，NAND FLASH 64M，SDRAM 64M。研究UBOOT的start.S时发现他本身有一段代码用来复制自身到SDRAM中去的，如下：
relocate: /* relocate U-Boot to RAM */
adr r0, _start /* r0 <- current position of code */
ldr r1, _TEXT_BASE /* defined position of code =0x33f8'0000*/
/* test if we run from flash or RAM */
cmp r0, r1 /* don't reloc during debug */
beq stack_setup
ldr r2, _armboot_start
ldr r3, _bss_start
sub r2, r3, r2
add r2, r0, r2
copy_loop:
ldmia r0!, {r3-r10}
stmia r1!, {r3-r10}
cmp r0, r2
ble copy_loop
为什么资料上还要移植vivi中的一大段代码（如下），用来做为复制uboot代码到SDRAM？两个功能有区别吗？
#ifdef CONFIG_S3C2410_NAND_BOOT
copy_myself:
mov r10, lr
@ reset NAND
mov r1, #NAND_CTL_BASE
ldr r2, =0xf830 @ initial value
str r2, [r1, #oNFCONF] @ #define oNFCONF 0x00
ldr r2, [r1, #oNFCONF]
bic r2, r2, #0x800 @ enable chip
str r2, [r1, #oNFCONF]
mov r2, #0xff @ RESET command
strb r2, [r1, #oNFCMD] @ #define oNFCMD 0x04
mov r3, #0 @ wait
...
... |
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