RTEMS stack + TSIM-LEON2 weird behaviour

[Aitor.Viana.Sanchez at esa.int]

Hi all,

I've got some weird (for me) when executing the rtems-hello example in the 
tsim-leon2 professional version.

The example is from the rtems-4.7.99.2-1.0.3 version.

and the compiling options  CFLAGS="-msoft-float -qleon2".

OK, If I compile the example and disassemble it I got this:

40000000 <_text_start>:
40000000:       a0 10 00 00     mov  %g0, %l0
40000004:       29 10 00 04     sethi  %hi(0x40001000), %l4
40000008:       81 c5 20 00     jmp  %l4
4000000c:       a6 10 20 00     clr  %l3
40000010:       91 d0 20 00     ta  0

Now I execute the tsim-leon and put a break point in the 0x40000004 
address



 TSIM/LEON SPARC simulator, version 1.3.5 (professional version)

 Copyright (C) 2001, Gaisler Research - all rights reserved.
 For latest updates, go to http://www.gaisler.com/
 Comments or bug-reports to tsim at gaisler.com

using 64-bit time
serial port A on stdin/stdout
allocated 4096 K RAM memory, in 1 bank(s)
allocated 2048 K ROM memory
icache: 1 * 4 kbytes, 16 bytes/line (4 kbytes total)
dcache: 1 * 4 kbytes, 16 bytes/line (4 kbytes total)
section: .text, addr: 0x40000000, size 75936 bytes
section: .data, addr: 0x400128a0, size 3520 bytes
section: .jcr, addr: 0x40013660, size 4 bytes
read 424 symbols
tsim> +bp 0x40000004
breakpoint 1 at 0x40000004:  start + 0x4
tsim> 


I want to check the registers:

tsim> re

          INS       LOCALS      OUTS     GLOBALS
   0:  00000000   00000000   00000000   00000000
   1:  00000000   00000000   00000000   00000000
   2:  00000000   00000000   00000000   00000000
   3:  00000000   00000000   00000000   00000000
   4:  00000000   00000000   00000000   00000000
   5:  00000000   00000000   00000000   00000000
   6:  00000000   00000000   00000000   00000000
   7:  00000000   00000000   00000000   00000000

 psr: 00000080   wim: 00000000   tbr: 00000000   y: 00000000

 pc:  00000000  00000000  unimp
 npc: 00000004  00000000  unimp
tsim> 

Everything ok. 

I start the execution

tsim> g
resuming at 0x40000000

breakpoint 1  start + 0x4
tsim> 

and I check again the registers

tsim> re

          INS       LOCALS      OUTS     GLOBALS
   0:  00000000   00000000   00000000   00000000
   1:  00000000   00000000   00000000   00000000
   2:  00000000   00000000   00000000   00000000
   3:  00000000   00000000   00000000   00000000
   4:  00000000   00000000   00000000   00000000
   5:  00000000   00000000   00000000   00000000
   6:  40400000   00000000   403FFE80   00000000
   7:  00000000   00000000   00000000   00000000

 psr: 000010E0   wim: 00000002   tbr: 00000000   y: 00000000

 pc:  40000004  29100004  sethi %hi(0x40001000), %l4
 npc: 40000008  81c52000  jmp   %l4


tsim>

I think only ONE instruction should have been executed (40000000:       a0 
10 00 00     mov  %g0, %l0) but we can see that the %sp registers is 
already set. Who set this register up?




Cheers,

Aitor

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