129 lines
1.6 KiB
ArmAsm
129 lines
1.6 KiB
ArmAsm
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#define MEM_END 0x00800000 /* Memory size 8Mb */
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#undef CRT_DEBUG
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.macro PUTC CHAR
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#ifdef CRT_DEBUG
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moveq #\CHAR, %d7
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jsr putc
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#endif
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.endm
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.global _start
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.global _rambase
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.global _ramvec
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.global _ramstart
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.global _ramend
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.data
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/*
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* Set up the usable of RAM stuff
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*/
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_rambase:
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.long 0
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_ramvec:
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.long 0
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_ramstart:
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.long 0
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_ramend:
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.long 0
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.text
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_start:
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/*
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* Setup initial stack
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*/
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/* disable all interrupts */
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movew #0x2700, %sr
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movel #-1, 0xfffff304
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movel #MEM_END-4, %sp
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PUTC '\r'
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PUTC '\n'
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PUTC 'A'
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PUTC 'B'
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/*
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* Determine end of RAM
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*/
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movel #MEM_END, %a0
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movel %a0, _ramend
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PUTC 'C'
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/*
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* Move ROM filesystem above bss :-)
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*/
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moveal #_sbss, %a0 /* romfs at the start of bss */
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moveal #_ebss, %a1 /* Set up destination */
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movel %a0, %a2 /* Copy of bss start */
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movel 8(%a0), %d1 /* Get size of ROMFS */
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addql #8, %d1 /* Allow for rounding */
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andl #0xfffffffc, %d1 /* Whole words */
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addl %d1, %a0 /* Copy from end */
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addl %d1, %a1 /* Copy from end */
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movel %a1, _ramstart /* Set start of ram */
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1:
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movel -(%a0), %d0 /* Copy dword */
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movel %d0, -(%a1)
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cmpl %a0, %a2 /* Check if at end */
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bne 1b
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PUTC 'D'
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/*
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* Initialize BSS segment to 0
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*/
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lea _sbss, %a0
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lea _ebss, %a1
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/* Copy 0 to %a0 until %a0 == %a1 */
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2: cmpal %a0, %a1
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beq 1f
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clrl (%a0)+
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bra 2b
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1:
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PUTC 'E'
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/*
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* Load the current task pointer and stack
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*/
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lea init_thread_union, %a0
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lea 0x2000(%a0), %sp
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PUTC 'F'
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PUTC '\r'
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PUTC '\n'
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/*
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* Go
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*/
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jmp start_kernel
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/*
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* Local functions
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*/
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#ifdef CRT_DEBUG
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putc:
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moveb %d7, 0xfffff907
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1:
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movew 0xfffff906, %d7
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andw #0x2000, %d7
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beq 1b
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rts
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#endif
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