|
| execute NetBSD kernel
|
| written by ITOH Yasufumi
| public domain
|
| $NetBSD: execkern.S,v 1.4 2011/02/21 02:31:58 itohy Exp $
#include <machine/asm.h>
#include "execkern.h"
#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 load address
|
| a3+4 section #1 image top address
| a3+8 section #1 size
| a3+12 section #1 gap size
| : :
| a3+n-12 section #XK_NSEC image top address
| a3+n-8 section #XK_NSEC size
| a3+n-4 section #XK_NSEC gap size
|
| a3+n (reserved) (d5)
| a3+n+4 bootdev (d6)
| a3+n+8 boothowto (d7)
| a3+n+12 entry address (absolute address)
#ifndef XK_NO_C_INTERFACE
.text
.even
ENTRY_NOPROFILE(exec_kernel)
addql #4,%sp
moveal %sp@+,%a3 | struct execkern_arg *
#endif
moveal %a3@+,%a1 | load address
movel %a1,%d3
|
| copy image
|
movel #XK_NSEC-1,%d2
Lloop:
moveal %a3@+,%a0 | section image address
movel %a3@+,%d0 | section size
movel %d0,%d1
jbsr copy
movel %a3@+,%d0 | section gap
jbsr clear
dbra %d2,Lloop
| 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 (end of kernel)
movel SRAM_MEMSZ,%sp@- | arg #2 (RAM size from SRAM)
movel %d3,%sp@- | arg #1 (load address)
#if 0
movel %a3@+,%d5 | (reserved)
movel %a3@+,%d6 | boot device
movel %a3@+,%d7 | boot howto
movel %a3@+,%a0 | entry address
#else /* optimized */
moveml %a3@+,%d5-%d7/%a0
#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
| 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
|
| utility routines
|
| copy %d0 bytes from higher (%a0) to lower (%a1) address
1: moveb %a0@+,%a1@+
copy: subql #1,%d0
bpls 1b
rts
| clear %d0 bytes at %a1
| do nothing if %d0 is zero
1: clrb %a1@+
clear: subql #1,%d0
bpls 1b
rts
