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https://github.com/trezor/trezor-firmware.git
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42 lines
1.3 KiB
ArmAsm
42 lines
1.3 KiB
ArmAsm
.syntax unified
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.text
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.global reset_handler
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.type reset_handler, STT_FUNC
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reset_handler:
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// setup environment for subsequent stage of code
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ldr r0, =ccmram_start // r0 - point to beginning of CCMRAM
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ldr r1, =firmware_header_start // r1 - point to byte where firmware header starts
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ldr r2, =0 // r2 - the word-sized value to be written
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bl memset_reg
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ldr r0, =sram_start // r0 - point to beginning of SRAM
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ldr r1, =sram_end // r1 - point to byte after the end of SRAM
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ldr r2, =0 // r2 - the word-sized value to be written
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bl memset_reg
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// copy data in from flash
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ldr r0, =data_vma // dst addr
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ldr r1, =data_lma // src addr
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ldr r2, =data_size // size in bytes
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bl memcpy
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// setup the stack protector (see build script "-fstack-protector-all") with an unpredictable value
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bl rng_get
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ldr r1, = __stack_chk_guard
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str r0, [r1]
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// re-enable exceptions
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// according to "ARM Cortex-M Programming Guide to Memory Barrier Instructions" Application Note 321, section 4.7:
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// "If it is not necessary to ensure that a pended interrupt is recognized immediately before
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// subsequent operations, it is not necessary to insert a memory barrier instruction."
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cpsie f
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// enter the application code
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bl main
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b shutdown_privileged
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.end
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