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181 lines
4.3 KiB
ArmAsm
181 lines
4.3 KiB
ArmAsm
/*
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* crt0.S -- startup codes for CK-CPU.
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*
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* Define a exception vector table
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*
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* Initial PSR register.
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* Initial VBR register, relocate exception vector table.
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* Initial sp(stack pointer) register.
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* Initial MGU (for ckcpu having MGU)
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* Initial Cache.
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* Initial SPM (for ckcpu having SPM).
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* Initial BSS section to "0"
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* Then goto "main".
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*
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* Copyright (c) 2020 C-SKY Microsystems All rights reserved.
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*/
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.file "crt0.S"
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/*
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* MGU & CACHE macro from "ck5a6.h"
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*
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* CONFIG_CKCPU_MGU_BLOCKS ---- MGU block priority setting value
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* CONFIG_CKCPU_MGU_REGION(1-4)
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* ---- MGU (1-4) block base address and size.
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* CONFIG_CKCPU_ICACHE ---- Instruction cache enable
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* CONFIG_CKCPU_DCACHE ---- Data cache enable
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*
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* SPM macro from "ck5a6.h"
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*
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* CONFIG_CKCPU_SPM ---- CKCPU having SPM ?
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* CONFIG_CKCPU_SPM_ENABLE ---- SPM Enable
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* CONFIG_CKCPU_ISPM_MODE ---- Instruction SPM Mode(cache/local memory)
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* CONFIG_CKCPU_DSPM_MODE ---- Data SPM Mode (cache/local memory)
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* CONFIG_CKCPU_ISPM_ADDRESS
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* ---- Instruction SPM external memory base address,
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* Just for Local Memory Mode
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* CONFIG_CKCPU_DSPM_ADDRESS
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* ---- Data SPM external memory base address, Just
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* for Local Memory Mode
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* CONFIG_CKCPU_ISPM_TRANSFER
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* ---- The content in Instruction SPM must be
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* initialed, Just for Local Memory Mode
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* CONFIG_CKCPU_DSPM_TRANSFER
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* ---- The content in Data SPM must be initialed,
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* Just for Local Memory Mode
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*/
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/*
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* For importing variable or functions from script file "ckcpu.ld".
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*/
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.import __stack /* The stack pointer from linking script file */
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.import __fstack /* The fast interrupt stack from linking script file */
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.import __sbss /* The end of bss from linking script file */
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.import __ebss /* The end of bss from linking script file */
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.import __csky_exit /* For QEMU exit. */
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/*
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* For importing variable or functions from other c or assemble files.
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*/
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.import main /* The c codes entry */
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.import spm_init /* Initial ckcpu SPM */
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.import exit
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.import __libc_init_array
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/*
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* For importing variable or functions from entry.S.
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*/
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/* default exception service routine */
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/*
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.import default_exception_handler
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*/
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/* For exporting varialbe or functions */
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.export ckcpu_vsr_table /* Vector table base address. */
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.export __start /* The system entry. */
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.text
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/* Vector table space. */
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.align 10
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ckcpu_vsr_table:
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.rept 128
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.long __default_exception_handler
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.endr
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/* The ckcpu startup codes. */
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.text
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/*
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*
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* This is the codes first entry point. This is where it all
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* begins...
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*/
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.long __start
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__start:
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/*
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* Init psr value, enable exception, disable interrupt and fast interrupt.
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* psr = 0x80000100
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*/
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lrw r7, 0
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bseti r7, 31
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bseti r7, 8
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mtcr r7, psr
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/*
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* Setup initial vector base table for interrupts and exceptions
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*/
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lrw r6, ckcpu_vsr_table
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mtcr r6, vbr
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/* Initialize the normal stack pointer from the linker definition. */
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lrw r7, __stack
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mov sp, r7
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#ifdef FAST_INTERRUPT_ENABLE
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/* Initialize the fast interrupt stack pointer . */
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psrset af
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lrw r6, __fstack
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mov sp, r6
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psrclr af
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#endif
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/*
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* Initial CKCPU MGU & Cache
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* Step 1: Disable MGU & Cache.
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*/
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movi r7, 0
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mtcr r7, cr18
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#if 0
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/*
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* Zero out the bss region.
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* NOTE: __sbss must align 4
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*/
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lrw r7, __sbss /* Get start of bss from linking script file */
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lrw r6, __ebss /* Get end of bss from linking script file */
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subu r6, r7 /* Calculate size of bss */
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lsri r6, r6, 2 /* Size of whole words */
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cmpnei r6, 0
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bf __goto_c
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movi r5, 0 /* Set zero value to write */
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2:
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stw r5, (r7) /* Zero next word */
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addi r7, 4 /* Increase bss pointer */
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subi r6, 1 /* Decrease counter */
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cmpnei r6, 0
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bt 2b /* Repeat for all bss */
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#endif
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/*
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* Assember start up done, C codes start here.
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*/
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__goto_c:
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/*jsri main*/
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lrw r5, __libc_init_array
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jsr r5
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/*Set the argc and argv to NULL. */
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movi r0, 0
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movi r1, 0
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lrw r5, main
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jsr r5
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/* Should never get here. */
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jbsr exit
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__csky_exit:
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br __csky_exit
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__default_exception_handler:
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lrw r4, __csky_exit
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movi r5, 0x2
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stw r5, (r4, 0)
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br __default_exception_handler
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rte
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.data
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.align 4
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__stack_bottom:
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.rept 128
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.long 0x0
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.endr
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