Op Thu, 26 Jun 2008 01:10:21 -0500 schreef Mohan kumar:
> Hi thanks for your reply,
>
> the puzzling question that rocks my mind is why should they terminate
the
> stack by subtracting 64 with the stack pointer(r1)
>
> addi r1,r11,__stackstart_pt@[EMAIL PROTECTED]
> addi r1,r11,__stackstart_pt@[EMAIL PROTECTED]
> addi r0,r0,0
> stwu r0,-64(r1)
>
> 1. first two lines of code have defined the stack pointer(r1)
> 2. third lines has cleared register r0.
> 3. r1 is the stack pointer(sp) and sp is already initialised by first
> two lines. and in the fourth line, they carry out this operation on
> stack pointer "stwu r0,-64(r1)" Instruction does the following.
> => Effective address(EA) r1-64
> => EA is stored in stack pointer(r1)
Wrong. EA is nowhere stored
> => value at the effective address is cleared to zero.
>
> Why should the stack pointer will now hold the address given by EA.?
>
> Any guess?
No guess, EA is only used to determine the address where the value of r0
is
to be stored.
--
Coos
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