NetBSD/sys/arch/x68k/stand/common/execkern.S

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|
| execute NetBSD kernel
|
| written by Yasha (ITOH Yasufumi)
| public domain
|
| $NetBSD: execkern.S,v 1.2 2001/06/12 16:57:27 minoura Exp $
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/* XXX this value is from <machine/exec_aout.h> */
#define __LDPGSZ 8192
#define MFP 0x00E88000 /* MFP */
#define MFP_IERA (MFP+0x07) /* (B) interrupt enable reg A */
#define MFP_IERB (MFP+0x09) /* (B) interrupt enable reg B */
#define MFP_RSR (MFP+0x2B) /* (B) USART receiver status reg */
#ifndef SRAM_MEMSZ
#define SRAM 0x00ED0000 /* SRAM start addr */
#define SRAM_MEMSZ (SRAM + 8) /* (L) size of main memory */
#endif
| %a3+0 kernel image top address (a.out header is excluded)
| %a3+4 load address
| %a3+8 text size
| %a3+12 data size
| %a3+16 bss size
| %a3+20 symbol size
| %a3+24 (reserved) (%d5)
| %a3+28 bootdev (%d6)
| %a3+32 boothowto (%d7)
| %a3+36 entry address (absolute address)
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#ifndef XK_NO_C_INTERFACE
.text
.even
ENTRY_NOPROFILE(exec_kernel)
addql #4,%sp
moveal %sp@+,%a3 | struct execkern_arg *
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#endif
moveal %a3@+,%a0 | image address
moveal %a3@+,%a1 | load address
movel %a1,%d3
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|
| copy image
|
| copy text segment
movel %a3@+,%d0 | text size
movel %d0,%d1
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jbsr copy
| clear gap between text and data
negl %d1
andil #__LDPGSZ-1,%d1
movel %d1,%d0 | gap size between text and data
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jbsr clear
| copy data segment
movel %a3@+,%d0 | data size
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jbsr copy
| clear bss
movel %a3@+,%d0 | bss size
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jbsr clear
| copy symbol table
movel %a3@+,%d0 | symbol table size
movel %d0,%a1@+
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beqs Lnotable
jbsr copy
| copy string table size
movel %a0@+,%d0
movel %d0,%a1@+
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beqs Lnotable
| copy string table
subql #4,%d0 | table size is already copied
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jbsr copy
Lnotable:
| stop MFP interrupts (for compatibility)
clrb MFP_IERA
clrb MFP_IERB
clrb MFP_RSR
|
| execute kernel
| start(load_addr, mem_max, kernel_end)
|
movel %a1,%d0
addql #3,%d0
andib #0xFC,%d0
subl %d3,%d0
movel %d0,%sp@- | arg #3 (kernel size)
movel SRAM_MEMSZ,%sp@- | arg #2 (RAM size from SRAM)
movel %d3,%sp@- | arg #1 (load address)
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#if 0
movel %a3@+,%d5 | (reserved)
movel %a3@+,%d6 | boot device
movel %a3@+,%d7 | boot howto
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movel %a3@+,%a0 | entry address
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#else /* optimized */
moveml %a3@+,%d5-%d7/%a0
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#endif
| clear unused registers
moveq #0,%d0
moveq #0,%d1
moveq #0,%d2
moveq #0,%d3
moveq #0,%d4
moveal %d0,%a1
moveal %d0,%a2
moveal %d0,%a3
moveal %d0,%a4
moveal %d0,%a5
moveal %d0,%a6
jsr %a0@ | execute NetBSD kernel
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| NOTREACHED
| ??? returned from kernel -- issue software reset
subal %a1,%a1
moveml 0x00ff0000,#0x0101 | get RESET vectors (%d0: ssp, %a0: pc)
moveml #0x0101,%a1@ | put them at 0x00000000 (for Xellent)
.long 0x4E7B9801 | movec %a1,%vbr
jmp %a0@ | go to reset address
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|
| utility routines
|
| copy %d0 bytes from higher (%a0) to lower (%a1) address
1: moveb %a0@+,%a1@+
copy: subql #1,%d0
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bpls 1b
rts
| clear %d0 bytes at %a1
| do nothing if %d0 is zero
1: clrb %a1@+
clear: subql #1,%d0
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bpls 1b
rts