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ARM vectors.S question. Thank you.
- From: "QiangHuang" <jameshq at liverpool dot ac dot uk>
- To: "Ecos-Discuss" <ecos-discuss at sources dot redhat dot com>
- Date: Thu, 19 Jun 2003 23:24:20 +0100
- Subject: [ECOS] ARM vectors.S question. Thank you.
Hi :
Can anyone give me some suggestion about the following code? thanks a
lot.
memory map:
SECTION_fixed_vectors (ram, 0x20, LMA_EQ_VMA)
SECTION_rom_vectors (ram, 0x40000, LMA_EQ_VMA)
SECTION_text (ram, ALIGN (0x4), LMA_EQ_VMA)
ARM vectors.S
................
ldr r1,=__exception_handlers
// **Question 1** Is r1 = 0x40000 here ???
..........
#ifdef CYGHWR_HAL_ARM_ICE_THREAD_SUPPORT
ldr r2,=ice_thread_vector
// **Question 2** by here what is value of r2 by now, is
r2=0x20+offset(ice_thread_vector to fixed_vectors) ???? Is this Correct???
sub r2,r2,r1 // compute fixed (low memory) address
// **Question 3** if the above correct why this is needed??? what is
value of r2=r2-r1 ?? r2 = r2-0x40000??? what is going here, how the address
is defined??
ldr r3,=0x4D494345 // 'MICE'
str r3,[r2],#4
ldr r3,=hal_arm_ice_thread_handler
str r3,[r2],#4
mov r3,#1
str r3,[r2],#4
ldr r3,=0x47444220 // 'GDB '
str r3,[r2],#4
#endif // CYGHWR_HAL_ARM_ICE_THREAD_SUPPORT
Thanks a lot.
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