[U-Boot-Users] PPC 405 _start code - Clarification

[Wolfgang Denk]

In message <EGEGIJHKDKJGAJMGIDPNOEHHCCAA.jwalden at digitalatlantic.com> you wrote:
> 
> what I expect to see it what I see in /cpu/start.S which looks like:
> 
> 	.text
> 	.long	0x27051956		/* U-Boot Magic Number			*/
> 	.globl	version_string
> version_string:
> 	.ascii U_BOOT_VERSION
> 	.ascii " (", __DATE__, " - ", __TIME__, ")"
> 	.ascii CONFIG_IDENT_STRING, "\0"

Let's ignore this part for now - you should find it at offset 0x0000.
_start is at offset 0x0100:

> _start:
...
> 	addi	r4,r0,0x0000
> 	mtspr	sgr,r4
> 	mtspr	dcwr,r4
> 
> 
> Instead I see:
> 
> fff80100 <_start>:
> fff80100:	38 80 00 00 	li	r4,0
> fff80104:	7c 99 eb a6 	mtsgr	r4
> fff80108:	7c 9a eb a6 	mtdcwr	r4
> fff8010c:	7c 94 f3 a6 	mtesr	r4
> fff80110:	7c 9a f3 a6 	mttcr	r4
> fff80114:	7c 81 03 a6 	mtxer	r4
> fff80118:	7c 96 f3 a6 	mtevpr	r4
> fff8011c:	38 80 10 00 	li	r4,4096
> 
> So hence I am confused....

You confuse me. Why are you confused?

	"addi    r4,r0,0x0000"	== "li      r4,0"
	"mtspr   sgr,r4"	== "mtsgr   r4"
	"mtspr   dcwr,r4"	== "mtdcwr  r4"
	...

Looks identical to me.

Best regards,

Wolfgang Denk

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