| file: boot.S
| author: chapuni(webmaster@chapuni.com)
| ITOH Yasufumi
|
| $NetBSD: boot.S,v 1.19 2020/01/28 11:57:22 isaki Exp $
|
| (1) IPL (or previous stage loader) loads first 1KB of this primary
| bootloader to (*). (*) is 0x2000 (from FD) or 0x2400 (from SASI/SCSI).
|
| (2) The first 1KB loads full primary bootloader (including first 1KB) from
| the boot partition to 0x3000. And jump to there.
|
| (3) The full primary bootloader loads the secondary bootloader known as
| /boot from its filesystem to 0x6000. And jump to there.
|
| Therefore, The first 1KB must be relocatable.
| The first 1KB must be smaller than or equal to 1024 bytes.
|
| (1) -> (2) -> (3)
| +------------+ +------------+ +------------+ 0x000000
| : : : : : :
| +------------+ +------------+ +------------+ (*)
| | first 1KB | | first 1KB | | first 1KB |
| +------------+ +------------+ +------------+ (*)+0x400
| : : : : : :
| : : +------------+ +------------+ 0x003000
| : : |full primary| |full primary|
| : : |boot loader | |boot loader |
| : : |(text+data) | |(text+data) |
| : : +------------+ +------------+ 0x005000
| : : |(bss) | |(bss) |
| : : +------------+ +------------+ 0x006000
| : : : : | /boot |
| : : : : +------------+
| : : : : : :
| ~ ~ ~ ~ ~ ~
| : : : :<-SP : :<-SP
| + - - - - - -+ + - - - - - -+ + - - - - - -+ 0x100000
| : : : : : :
|
#include <machine/asm.h>
#include "iocscall.h"
#define SRAM 0x00ED0000
#define SRAM_MEMSZ (SRAM + 8)
#define MINMEM 0x00400000
#define BOOT_ERROR(s) jbsr boot_error; .asciz s; .even
.globl _C_LABEL(bootufs)
.text
ASENTRY_NOPROFILE(start)
ASENTRY_NOPROFILE(top)
bras _ASM_LABEL(entry0)
.ascii "SHARP/"
.ascii "X680x0"
.word 0x8199,0x94e6,0x82ea,0x82bd
.word 0x8e9e,0x82c9,0x82cd,0x8cbb
.word 0x8ec0,0x93a6,0x94f0,0x8149
.word 0
| d4 ¤Ë¤Ï¤¹¤Ç¤Ë SCSI ID ¤¬Æþ¤Ã¤Æ¤¤¤ë
ASENTRY_NOPROFILE(entry0)
moveml %d0-%d7/%a0-%a7,_C_LABEL(startregs)
lea TEXTADDR:W,%a5 | set base ptr
#define _RELOC(adr) %a5@(((adr)-top):W)
#define ASRELOC(var) _RELOC(_ASM_LABEL(var))
#define RELOC(var) _RELOC(_C_LABEL(var))
lea RELOC(__bss_start),%a1
bra _ASM_LABEL(entry)
| Disklabel= 404bytes
| Since LABELOFFSET in <machine/disklabel.h> is 0x40,
| entry must be after 0x000001d4 (0x000f01d4)
.org 0x40
disklabel:
.space 404
ASENTRY_NOPROFILE(entry)
movew #_end-1,%d0 | bss end (low word only)
| clear out bss (must be <= 64KB)
subw %a1,%d0
clrbss: clrb %a1@+
dbra %d0,clrbss
movel %d4,RELOC(ID) | SCSI ID (if booted from SCSI)
lea 0x00100000,%sp | set system stack
lea %a5@,%a1 | set load address
| a1 will be used later for IOCS calls
| we use 68020 instructions, and check MPU beforehand
|
| here d0.w = -1, and the above "subw a1,d0" = 0x9049, and
| if MPU <= 010 loads 0x49,
| if MPU >= 020 loads 0x90.
| This is a move, not a tst instruction
| because pc-relative tsts are not available on 000/010.
chkmpu: moveb %pc@(clrbss-chkmpu-2:B,%d0:W:2),%d0 | 103B 02xx
jmi mpuok | MC68020 or later
BOOT_ERROR("MPU 68000?")
mpuok: | XXX check for MMU?
IOCS(__BOOTINF)
lsll #8,%d0 | clear MSByte
lsrl #8,%d0 |
movel %d0,RELOC(BOOT_INFO)
|
| 0x80...0x8F SASI
| 0x90...0x93 Floppy
| 0xED0000...0xED3FFE SRAM
| others ROM (SCSI?)
|
movel %d0,%d1
clrb %d1
tstl %d1
jne boot_ram_rom
|
| SASI or Floppy
|
movel %d0,%d2
andib #0xFC,%d0
cmpib #0x90,%d0
jne boot_dev_unsupported | boot from SASI?
|
| Floppy
|
moveb %d2,%d0
andib #0x03,%d0 | drive # (head=0)
jbsr check_fd_format
moveml %d0-%d1,RELOC(FDSECMINMAX) | min and max sec #
lslw #8,%d2
moveq #0x70,%d1
orw %d2,%d1 | PDA*256 + MODE
movel %d1,RELOC(FDMODE)
movel %d0,%d2 | read position (first sector)
movel #8192,%d3 | read bytes
IOCS(__B_READ)
jra boot_read_done
#include "chkfmt.s"
boot_ram_rom:
movel %d0,%d1
swap %d1
cmpiw #0x00ED,%d1
jne boot_SCSI
| boot from SRAM?
boot_dev_unsupported:
BOOT_ERROR("unsupported boot device")
|
| volatile void BOOT_ERROR(const char *msg);
| print error message, wait for key press and reboot
|
booterr_msg: .ascii "\r\n\n"
.ascii BOOT
.asciz ": "
reboot_msg: .asciz "\r\n[Hit key to reboot]"
.even
ENTRY_NOPROFILE(BOOT_ERROR)
addql #4,%sp
boot_error: lea %pc@(booterr_msg),%a1
IOCS(__B_PRINT)
moveal %sp@+,%a1
IOCS(__B_PRINT)
lea %pc@(reboot_msg),%a1
IOCS(__B_PRINT)
| wait for a key press (or release of a modifier)
IOCS(__B_KEYINP)
| issue software reset
trap #10
| NOTREACHED
|
| ROM boot ... probably from SCSI
|
boot_SCSI:
#ifdef SCSI_ADHOC_BOOTPART
|
| Find out boot partition in an ad hoc manner.
|
| get block length of the SCSI disk
SCSIIOCS(__S_READCAP) | using buffer at a1
tstl %d0
jeq 1f
BOOT_ERROR("READCAP failed")
1: moveq #0,%d5
moveb %a1@(6),%d5 | 1: 256, 2: 512, 4: 1024
lsrb #1,%d5 | 0: 256, 1: 512, 2: 1024
movel %d5,RELOC(SCSI_BLKLEN)
| find out the start position of the boot partition
| XXX VERY AD HOC
|
| ROM firmware:
| pass read pos (in block #) in d2
| Human68k-style partition table does not exist
| d2 is 4 at the maximum
| SCSI IPLs (genuine and SxSI):
| pass read pos (in kilobytes) in d2
| d2 is bigger than 0x20
| partition table on the memory is destroyed
| BOOT MENU Ver.2.22:
| passes partition table entry address in a0
| d2 is cleared to zero
| No other IPL is supported. XXX FIXME
tstl %d2
jne sc1
| no information in d2 -- probably from BOOT MENU
| a0 points the partiion table entry
movel %a0@(0x0008),%d2 | in KByte
sc1: cmpl #0x20,%d2
jcs sc2
lsll #8,%d2 | clear MSByte
lsrl #6,%d2 |
lsrl %d5,%d2 | in sector
sc2:
| read entire boot
moveq #8192/256,%d3 | size is 8KB
lsrl %d5,%d3 | in sector
jbsr scsiread | read at %a1
cmpil #5,%d2
bcc sc3
movql #0,%d2
sc3: movel %d2,RELOC(SCSI_PARTTOP)
#else
moveq #1,%d5 | 512bytes/sec
movel %d5,%sp@-
moveq #8192/512,%d3 | Æɤ߹þ¤á¤ëºÇÂ祵¥¤¥º
moveq #0x40,%d2 | ¤¤¤ï¤æ¤ë·è¤áÂǤÁ(sd*a ¤Î¤ß)
SCSIIOCS(__S_READ)
#endif
boot_read_done:
jmp first_kbyte
read_error: BOOT_ERROR("read error")
#undef RELOC
#undef ASRELOC
#undef _RELOC
|
| read SCSI
|
| input: d2.l: pos in sector
| d3.l: len in sector
| d4: target SCSI ID
| d5: sector length (0: 256, 1: 512, 2: 1024)
| a1: buffer address
| destroy:
| d0, d1, a1
|
scsiread:
moveml %d2-%d3/%d6-%d7/%a2,%sp@-
| if (pos >= 0x200000 || (len > 255 && pos + len >= 0x200000))
| use READEXT
| else
| use READ
moveq #0x20,%d0
swap %d0 | d0.l = 0x00200000
moveq #0,%d6
subqb #1,%d6 | d6.l = 255
moveq #8,%d7
addb %d5,%d7 | d7.b = (sector length: 0-2) + 8
cmpl %d0,%d2
jcc scsiread_ext
moveq #__S_READ,%d1
cmpl %d3,%d6
jcc scsiread_noext
subl %d2,%d0 | d0.0 = 0x200000 - pos
cmpl %d0,%d3 | <= len
jcs scsiread_noext | no
scsiread_ext: | use READEXT
extw %d6 | d6.l = 65535
moveq #__S_READEXT,%d1
scsiread_noext: | use READ
loop_scsiread:
| d1: SCSI IOCS call #
| d6: max sector count at a time
movel %d3,%a2 | save original len in a2
cmpl %d3,%d6
jcc 1f
movel %d6,%d3
1: IOCS(__SCSIDRV) | SCSIIOCS(d1)
tstl %d0
jne read_error
movel %d3,%d0 | addr += read count << (8 + sec len)
asll %d7,%d0
addl %d0,%a1
exg %d3,%a2 | restore original len to d3
addl %a2,%d2 | pos += read count
subl %a2,%d3 | len -= read count
jne loop_scsiread
moveml %sp@+,%d2-%d3/%d6-%d7/%a2
rts
|
| The former part must reside in the first 1KB.
|
.globl first_kbyte
first_kbyte:
|--------------------------------------------------------------------------
|
| The latter text+data part is not accessible at the first boot time.
| PC-relative can be used from here.
|
| Initialize the screen here. Some IPL (060turbo ROM or
| genuine boot selector) don't initialize the screen.
| Such initialization should be done as early as possible
| but it's too severe to place it in first_kbyte area.
| Therefore do it here.
moveq #0x10,%d1
IOCS(__CRTMOD)
jmp _C_LABEL(bootufs) | 0x0Fxxxx ¤ËÈô¤ó¤Ç¤æ¤¯
.word 0
| int badbaddr __P((void *adr));
| check if the given address is valid for byte read
| return: 0: valid, 1: not valid
ENTRY_NOPROFILE(badbaddr)
lea 0x0008:W,%a1 | MPU Bus Error vector
moveq #1,%d0
lea %pc@(badr1),%a0
movew %sr,%sp@-
oriw #0x0700,%sr | keep out interrupts
movel %a1@,%sp@-
movel %a0,%a1@ | set bus error vector
movel %sp,%d1 | save sp
moveal %sp@(10),%a0
tstb %a0@ | try read...
moveq #0,%d0 | this is skipped on bus error
badr1: moveal %d1,%sp | restore sp
movel %sp@+,%a1@
movew %sp@+,%sr
rts
| void RAW_READ __P((void *buf, u_int32_t blkpos, size_t bytelen));
| inputs:
| buf: input buffer address
| blkpos: read start position in the partition in 512byte-blocks
| bytelen: read length in bytes
Lraw_read_buf=4+(4*11)
Lraw_read_pos_=Lraw_read_buf+4
Lraw_read_len=Lraw_read_buf+8
#ifdef SCSI_ADHOC_BOOTPART
| RAW_READ of physical disk
ENTRY_NOPROFILE(RAW_READ0)
moveq #0,%d0
jra raw_read1
#endif
ENTRY_NOPROFILE(RAW_READ)
#ifdef SCSI_ADHOC_BOOTPART
movel _C_LABEL(SCSI_PARTTOP),%d0
raw_read1:
#endif
moveml %d2-%d7/%a2-%a6,%sp@-
moveml %sp@(Lraw_read_buf),%d1-%d3
movel %d1,%a1
| d2.l: pos in 512byte-blocks
| d3.l: length in bytes
| a1 (=d1): buffer address
lea TEXTADDR:W,%a5 | set base ptr
#define _RELOC(adr) %a5@(((adr)-top):W)
#define ASRELOC(var) _RELOC(_ASM_LABEL(var))
#define RELOC(var) _RELOC(_C_LABEL(var))
tstb _RELOC(_C_LABEL(BOOT_INFO)+1) | simple check. may be incorrect!
beqs raw_read_floppy
raw_read_scsi:
movel RELOC(ID),%d4 | SCSI ID
#ifdef SCSI_ADHOC_BOOTPART
movel RELOC(SCSI_BLKLEN),%d5 | sector size: 0-2
| XXX length must be sector aligned
lsrl #8,%d3 | size in 256byte-blocks
lsrl %d5,%d3 | size in sector
bcss read_half | minimal error check
lsll #1,%d2 | X flag and d2: pos in 256byte-blocks
roxrl %d5,%d2 | pos in sector
addl %d0,%d2 | physical pos in sector
#else
moveq #1,%d5 | 512bytes/sec
moveq #9,%d0 | shift count
addl #511,%d3
lsrl %d0,%d3
bcss read_half | minimal error check
addl #0x40,%d2 | 'a' partition starts here
#endif
| jcc 1f
| BOOT_ERROR("out of seek") | pos exceeds 32bit
|1:
jbsr scsiread
bras raw_read_end
raw_read_floppy:
|
| Floppy read routine
|
| convert to seek position
asll #2,%d2 | size in 128byte-blocks
| sec = raw_read_pos (d2)
| sec >>= 7 + (sector length: 0-3)
lea RELOC(FDSECMINMAX),%a0
moveq #0,%d1
moveb %a0@,%d1 | d1: sector length (0-3)
lsrl %d1,%d2 | d2: pos in sector
bcss read_half | error check
| trk = sec / (# sectors)
| sec = sec % (# sectors)
moveb %a0@(7),%d1 | d1: max sector #
subb %a0@(3),%d1 | - min sector #
addqb #1,%d1 | d1: # sectors
divu %d1,%d2 | d2: (sec << 16) | track
| position = (sec length << 24) | (track/2 << 16)
| | (track%2 << 8) | (min sec # + sec)
movel %a0@,%d0 | d0: (sec len << 24) | min sec #
lsrw #1,%d2 | d2: (sec << 16) | (track / 2)
jcc 1f
bset #8,%d0 | |= (track % 2) << 8
1: swap %d2 | d2: ((track / 2) << 16) | sec
addl %d0,%d2 | d2: position
| read
movel RELOC(FDMODE),%d1 | PDA*256 + MODE
| B_READ (for floppy)
| d1.w: PDA x 256 + MODE
| PDA: 0x90 (drive 0) ... 0x93 (drive 3)
| MODE: bit6: MFM
| bit5: retry
| bit4: seek
| d2.l: position
| bit31-24: sector length (0: 128, 1: 256, 2: 512, 3: 1K)
| bit23-16: track # (0-79)
| bit15-08: side (0 or 1)
| bit07-00: sector # (1-)
| d3.l: read bytes
| a1: read address
| return:
| d0: bit 31-24 ST0
| bit 23-16 ST1
| bit 15- 8 ST2
| bit 7- 0 C
| -1 on parameter error
| destroy: d0, d2, d3, a1
IOCS(__B_READ)
andil #0xf8ffff00,%d0 | check status (must be zero)
jne read_error
raw_read_end:
moveml %sp@+,%a2-%a6/%d2-%d7
rts
#undef _RELOC
#undef ASRELOC
#undef RELOC
read_half: BOOT_ERROR("read half of block")
ENTRY_NOPROFILE(B_PUTC)
movel %sp@(4),%d1
IOCS(__B_PUTC)
rts
ENTRY_NOPROFILE(B_PRINT)
movel %sp@(4),%a1
IOCS(__B_PRINT)
rts
|
| void memcpy(void *dst, const void *src, size_t count);
| void memmove(void *dst, const void *src, size_t count);
|
| small and slow memcpy...
| THIS FUNCTION DOES NOT CONFORM THE ANSI STANDARD
|
ENTRY_NOPROFILE(memcpy)
ENTRY_NOPROFILE(memmove)
lea %sp@(12),%a1
movel %a1@,%d1 | count
jeq Lmcpret
moveal %a1@-,%a0 | src
moveal %a1@-,%a1 | dest
cmpl %a1,%a0
jcc Lmcpfw
| copy backward
addal %d1,%a0
addal %d1,%a1
1: moveb %a0@-,%a1@-
subql #1,%d1
jne 1b
jra Lmcpret
Lmcpfw: | copy forward
1: moveb %a0@+,%a1@+
subql #1,%d1
jne 1b
Lmcpret:
| movel %sp@(8),%d0 | uncomment this to conform ANSI
rts
|
| global variables
|
BSS(ID, 4) | SCSI ID
BSS(BOOT_INFO, 4) | result of IOCS(__BOOTINF)
BSS(FDMODE, 4) | Floppy access mode: PDA x 256 + MODE
BSS(FDSECMINMAX, 8) | +0: (min sector) sector length
| +1: (min sector) track #
| +2: (min sector) side
| +3: (min sector) sector #
| +4: (max sector) sector length
| +5: (max sector) track #
| +6: (max sector) side
| +7: (max sector) sector #
#ifdef SCSI_ADHOC_BOOTPART
BSS(SCSI_PARTTOP, 4) | start sector of boot partition
BSS(SCSI_BLKLEN ,4) | sector len 0: 256, 1: 512, 2: 1024
#endif
