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68 lines
1.5 KiB
ArmAsm
68 lines
1.5 KiB
ArmAsm
/* Re-copy kernel image from given offset in a0 (length a1), and then
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* jump to entry point contained in a2. Copies data to location pointed
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* to in a3
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* Very naive.
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* ------------------------------------------------------------------
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* (c) 2008 Philippe Vachon <philippe@cowpig.ca>
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* Licensed under the GNU General Public License v3. See COPYING in the
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* source distribution for more details.
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*/
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#include <asm/regdef.h>
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#include <asm/asm.h>
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#define KSEG0 0x80000000
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#define CACHE_SIZE 0x4000
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#define ICACHE_INVALIDATE 0x00
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#define DCACHE_WRITEBACK_INVALIDATE 0x01
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#define CACHE_LINE_LEN 0x4
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EXPORT(_start)
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LEAF(_start)
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.set noreorder
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.set mips3
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1: lw s0, 0(a0) # load byte from address pointed to in a0
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sw s0, 0(a3) # copy byte to address pointed to in a3
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addiu a0, 4 # next location to read from
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addiu a3, 4 # next location to write to
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bnez a1, 1b # continue copying
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addi a1, -4 # subtract from remaining bytes to copy
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nop
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/* put the stack pointer up at top of memory */
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li a0, 4
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syscall
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nop
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li sp, KSEG0
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add sp, sp, v0
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/* invalidate the caches */
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li k0, KSEG0
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addi k1, k0, CACHE_SIZE
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2: cache ICACHE_INVALIDATE, 0(k0)
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cache DCACHE_WRITEBACK_INVALIDATE, 0(k0)
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ble k0, k1, 2b
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addi k0, CACHE_LINE_LEN
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/* jump to the kernel, setting up the firmware args appropriately */
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move a0, v0
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li a1, KSEG0
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li a3, 0
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li v0, 0
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jr a2 # jump to kernel entry point
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nop
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END(_start)
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