[ECOS] ARM vectors.S question. Thank you.

[QiangHuang]

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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