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[/] [ion/] [trunk/] [src/] [common/] [c_startup.s] - Rev 191
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#------------------------------------------------------------------------------- # startup.s -- C startup code common to all C programs. # # This code does the following: # 1.- Initialize the stack at the end of the bss area # 2.- Clear the bss area # 3.- Move the data section from FLASH to RAM (if applicable) # 4.- Call main() # 5.- Freeze in endless loop after main() returns, if it does # # The code does not initialize the caches or the hardware and does not include # the reset or trap vectors. # # This code was inherited from OpenCores' Plasma project. #------------------------------------------------------------------------------- # The stack size can be defined from the assembler command line # FIXME should use info from the link script .ifndef STACK_SIZE .set STACK_SIZE, 1024 # by default, reserve 1KB .endif # Reserve space for regular stack (BSS segment) .comm init_stack, STACK_SIZE .text .align 2 .global entry .ent entry entry: .set noreorder # (The linker script defined these symbols) la $gp, _gp # initialize global pointer la $5, __bss_start # $5 = .sbss_start la $4, _end # $2 = .bss_end la $sp, init_stack+STACK_SIZE-24 #initialize stack pointer # Clear BSS area $BSS_CLEAR: sw $0, 0($5) slt $3, $5, $4 bnez $3, $BSS_CLEAR addiu $5, $5, 4 # Move data section image from flash to RAM, if necessary. la $a0,data_start la $a1,data_load_start beq $a1,$a0,move_data_section_done nop la $s0,data_size beqz $s0,move_data_section_done nop move_data_section_loop: lw $t0,0($a1) addiu $a1,$a1,4 sw $t0,0($a0) addiu $a0,$a0,4 bnez $s0,move_data_section_loop addiu $s0,$s0,-4 move_data_section_done: jal main # init done; call main() nop $L1: j $L1 nop .end entry
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