mirror of
https://github.com/trezor/trezor-firmware.git
synced 2024-11-25 17:09:44 +00:00
86 lines
2.0 KiB
ArmAsm
86 lines
2.0 KiB
ArmAsm
.syntax unified
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.text
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.global memset_reg
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.type memset_reg, STT_FUNC
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memset_reg:
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// call with the following (note that the arguments are not validated prior to use):
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// r0 - address of first word to write (inclusive)
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// r1 - address of first word following the address in r0 to NOT write (exclusive)
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// r2 - word value to be written
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// both addresses in r0 and r1 needs to be divisible by 4!
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.L_loop_begin:
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str r2, [r0], 4 // store the word in r2 to the address in r0, post-indexed
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cmp r0, r1
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bne .L_loop_begin
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bx lr
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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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// we need to perform this in case an old bootloader
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// is starting the new firmware, these will be set incorrectly
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ldr r0, =0xE000ED08 // r0 = VTOR address
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ldr r1, =0x08010400 // r1 = FLASH_APP_START
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str r1, [r0] // assign
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ldr r0, =_stack // r0 = stack pointer
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msr msp, r0 // set stack pointer
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dsb
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isb
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ldr r0, =_ram_start // r0 - point to beginning of SRAM
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ldr r1, =_ram_end // r1 - point to byte after the end of SRAM
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ldr r2, =0 // r2 - the byte-sized value to be written
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bl memset_reg
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// copy .data section from flash to SRAM
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ldr r0, =_data // dst addr
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ldr r1, =_data_loadaddr // src addr
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ldr r2, =_data_size // length in bytes
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bl memcpy
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// enter the application code
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bl main
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// shutdown if the application code returns
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b shutdown
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.global shutdown
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.type shutdown, STT_FUNC
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shutdown:
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cpsid f
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ldr r0, =0
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mov r1, r0
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mov r2, r0
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mov r3, r0
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mov r4, r0
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mov r5, r0
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mov r6, r0
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mov r7, r0
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mov r8, r0
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mov r9, r0
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mov r10, r0
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mov r11, r0
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mov r12, r0
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ldr lr, =0xffffffff
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ldr r0, =_ram_start
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ldr r1, =_ram_end
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// set to value in r2
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bl memset_reg
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b . // loop forever
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.ltorg // dump literal pool (for the ldr ...,=... commands above)
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.global sv_call_handler
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.type sv_call_handler, STT_FUNC
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sv_call_handler:
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tst lr, #4
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ite eq
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mrseq r0, msp
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mrsne r0, psp
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b svc_handler_main
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.end
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