4.3BSD-UWisc/src/sys/mdec/tuboot.s
/*
* Copyright (c) 1980, 1986 Regents of the University of California.
* All rights reserved. The Berkeley software License Agreement
* specifies the terms and conditions for redistribution.
*/
/* "@(#)tuboot.s 7.1 (Berkeley) 6/5/86" */
/*
* VAX tu58 console cassette boot block
*
* Helge Skrivervik CSRG/UCB 18jun83
*
* Reads a program from a rt-11 directory on tape
* and executes it. Programs must be stripped of
* the header and is loaded ``bits as is''.
* You can return to this loader via ``ret'' as
* you are called ``calls $0,ent''.
* Error checking and recovery is almost nonexistant
* due to the severe space constraints.
*
* NOTE: Any changes to this program are likely to
* bring the size over 512 bytes ....
*
* Based on tp format bootstrap originally written by Thomas Ferrin.
*
*/
.set CTABLE,0x400 /* where to load the rad50 cnv table */
.set RELOC,0x70000
/* rt-11 directory definitions */
.set DIRBLK,6 /* rt-11 directory starts at block 6 */
.set FILSIZ,8 /* rt-11 direc entry offset for file size */
.set ENTSIZ,14 /* size of 1 rt-11 dir entry, bytes */
.set BLKSIZ,512 /* tape block size, bytes */
.set NUMDIR,2 /* no. of dir blocks on tape */
.set FNSIZ,8 /* size of rad50 filename + 2 */
.set NAME,2 /* direc entry offset for filename */
.set STATUS,1 /* direc entry offset for entry status */
/* rt-11 directory entry status */
.set RT_ESEG,8 /* end of directory segment */
.set RT_NULL,2 /* empty entry */
.set RT_FILE,4 /* valid file entry */
/* processor registers and bits */
.set RXCS,32
.set RXDB,33
.set TXCS,34
.set TXDB,35
.set RXCS_DONE,0x80
.set TXCS_RDY,0x80
.set TXCS_pr,7 /* bit position of TXCS ready bit */
.set RXCS_pd,7 /* bit position of RXCS done bit */
/* console storage registers and bits */
.set CSRS,0x1c
.set CSRD,0x1d
.set CSTS,0x1e
.set CSTD,0x1f
/* TU commands and bits */
.set TU_BREAK,1
.set TU_INIT,4
.set TU_CONTINUE,16
.set TU_READY,7 /* bit position of CSRS ready bit */
.set TU_PACKETLEN,8 /* length of readcom block */
/* local stack variables */
.set ext,-4 /* file ext. */
.set name,-20 /* 12 bytes for full name */
.set rt_name,-20-FNSIZ /* rad50 file name */
/* reboot flags for boot */
.set RB_ASK,3 /* ask name and come up single user */
/*
* Initialization.
*/
init:
.word 0 /* entry mask for dec monitor */
nop;nop;nop;nop;nop /* some no-ops for 750 boot rom to skip */
nop;nop;nop;nop;nop
movl $RELOC,fp /* core loc to which to move this program */
addl3 $rt_name,fp,sp /* set stack pointer; leave room for locals */
clrl r0
1:
movc3 $end,(r0),(fp) /* move boot up to relocated position */
jmp start+RELOC
start:
mtpr $TU_BREAK,$CSTS /* set break condition */
clrl r2 /* nulls */
bsbw xmit2 /* wait 2 character times */
mfpr $CSRD,r2 /* clear receive buffer */
movzwl $TU_INIT|(TU_INIT<<8),r2 /* load 2 INIT opcodes */
bsbw xmit2 /* xmit 'em */
1:
mfpr $CSRD,r7 /* get recv data */
cmpb r7,$TU_CONTINUE /* is it a continue flag? */
bneq 1b /* nope, look more */
movab name(fp),r4 /* start of filename storage */
clrq (r4) /* init name field */
clrq name+8(fp)
clrq rt_name(fp) /* init rad50 filename */
movzbl $'=,r0 /* prompt character */
bsbw putc /* output char to main console */
/*
* Read in a file name from console.
*/
movl r4,r1 /* loc at which to store file name */
nxtc:
bsbw getc /* get input char's in file name */
cmpb r0,$012 /* terminator ? */
beql nullc
movb r0,(r1)+
brb nxtc
nullc:
cmpl r4,r1
beql start /* restart if empty string */
clrb (r1) /* add null byte at end */
/*
* User-specified filename has been stored at name(fp),
* read the entire directory contents into low core.
*/
dirred:
movl $DIRBLK,r10 /* directory starts at block DIRBLK */
movl $(NUMDIR*BLKSIZ),r6 /* no. bytes in total dir */
clrl r11 /* start address */
bsbw taper /* read no. bytes indicated */
/*
* Read in the character conversion table which reside in block 1
* (the second block) on the cassette. Place it after the directory
* on low core (from 0x400).
*/
movl $1,r10 /* block number */
movl $BLKSIZ,r6 /* read one block */
bsbw taper
/*
* Convert the ascii filename to rad50.
* R4 still points to name(fp)
*/
movl $6,r3 /* max length of filename */
1:
cmpb $'.,(r4)+ /* look for '.' */
beql 1f
sobgtr r3,1b
incl r4 /* point past '.' if ext is present */
1:
clrb -1(r4) /* end name with null */
movl $3,r3 /* max length of extension */
movab ext(fp),r5 /* place extension here */
1:
movb (r4)+,(r5)+
beql 1f /* the string is null terminated */
sobgtr r3,1b
1:
movab name(fp),r4
movab rt_name(fp),r5 /* ptr to rad50 name */
bsbw rad50 /* convert filename */
movab ext(fp),r4
movab rt_name+4(fp),r5
bsbw rad50 /* convert extension */
/*
* Search entire directory for user-specified file name.
*/
movab rt_name(fp),r4 /* search for this file */
movl $10,r5 /* point to first file entry */
movzwl -2(r5),r10 /* r10 = block # where files begin */
2:
cmpc3 $6,NAME(r5),(r4) /* see if dir entry matches filename */
beql fndfil /* found match */
1:
addw2 FILSIZ(r5),r10 /* add file length to block pointer */
addl2 $ENTSIZ,r5 /* move to next entry */
# cpmb STATUS(r5),$RT_NULL /* check if deleted file */
# beql 1b /* not really necessary since deleted entries will fail */
/* to compare anyway */
cmpb STATUS(r5),$RT_ESEG /* check if end of segment */
bneq 2b
brw start /* entry not in directory; start over */
/*
* Found desired directory entry
*/
fndfil:
/* start block no., 2 bytes in r10 */
movzwl FILSIZ(r5),r6 /* file size (blocks) */
mull2 $BLKSIZ,r6 /* file size (bytes) */
cmpl r6,$RELOC-512 /* check if file fits below stack */
blss filok
brw start /* file too large */
/*
* Read in desired file from tape.
*/
filok:
movl r6,r5 /* start of bss space */
clrl r11 /* start address */
bsbb taper
/*
* Clear core.
*/
subl3 r5,$RELOC-4,r0 /* no. bytes to clear */
1:
clrb (r5)+
sobgtr r0,1b
/*
* Jump to start of file & execute.
*/
addl3 $20,fp,ap /* ?? */
clrl r5
movl $RB_ASK,r11
calls $0,(r5)
bad:
brw start
/*
* Read (r6) bytes from block (r10)
* into loc (r11).
*/
taper:
clrl r8 /* initialize checksum */
movab readcom,r0 /* read command packet addr */
movzbl $TU_PACKETLEN/2,r1 /* size of readcom block */
1:
movzwl (r0)+,r2 /* get 2 chars from block */
bsbb xmit /* xmit and update ckecksum */
sobgtr r1,1b /* loop if more */
/*
* Now do variable part of packet.
*/
movl r6,r2 /* byte count */
bsbb xmit
movl r10,r2 /* starting block number */
bsbb xmit
movzwl r8,r2 /* accumulated ckecksum */
bsbb xmit
/*
* Collect read packet from device.
*/
1:
bsbb recv2 /* get 2 packet characters */
decb r2 /* data packet? */
bneq 1f /* branch on end of data */
movzbl r1,r8 /* get byte count of packet */
/*
* Read data into memory.
*/
2:
bsbb recv1 /* get a char */
movb r1,(r11)+ /* stuff into memory */
sobgtr r8,2b /* loop if more */
bsbb recv2 /* skip checksum */
brb 1b /* read next packet */
/*
* End of data xfer; check for errors.
*/
1:
bsbb recv2 /* get success code */
tstl r1 /* error in read? */
blss 9f /* branch if status error */
movl $5,r0
1:
bsbb recv2 /* discard 10 bytes */
sobgtr r0,1b
rsb
/* Fatal error */
9:
movab ermsg,r1
1:
movb (r1)+,r0
beql bad
bsbb putc
brb 1b
/*
* Update checksum in r8 and xmit 2 characters.
*/
xmit:
addw2 r2,r8 /* update checksum */
adwc $0,r8 /* add in carry */
/* send the 2 characters contained in r2 */
xmit2:
bsbb 1f /* xmit one of 'em */
ashl $-8,r2,r2 /* get next char */
/* fall into... */
1:
mfpr $CSTS,r7 /* get xmit status */
bbc $TU_READY,r7,1b /* loop until ready */
mtpr r2,$CSTD /* send char */
rsb
/*
* Receive 2 characters, return in r2 and r1.
*/
recv2:
bsbb recv1 /* recv one of 'em */
/* fall into... */
/*
* Receive 1 character.
*/
recv1:
movzbl r1,r2 /* save previous byte */
1:
mfpr $CSRS,r7 /* get recv status */
bbc $TU_READY,r7,1b /* loop until ready */
mfpr $CSRD,r1 /* get char */
blss 9b /* branch on recv error */
rsb
getc:
mfpr $RXCS,r0
bbc $RXCS_pd,r0,getc /* receiver ready ? */
mfpr $RXDB,r0
extzv $0,$7,r0,r0
cmpb r0,$015
bneq putc /* echo and return */
bsbb putc /* carriage return */
# movb $0,r0
# bsbb putc /* delay */
movb $012,r0 /* send line feed and return */
putc:
mfpr $TXCS,r2
bbc $TXCS_pr,r2,putc /* transmitter ready ? */
mtpr r0,$TXDB
rsb
/*
* Convert the filename given from the console
* to radix 50 (rt-11) format.
*/
rad50:
clrw r1
bsbb getb50 /* get next ascii byte, exit if null */
mull3 $03100,r0,r1
bsbb getb50
mull3 $050,r0,r2
addl2 r2,r1
bsbb getb50
addl2 r0,r1 /* last byte, just add it in */
movw r1,(r5)+ /* save result */
brb rad50
getb50:
movzbl (r4)+,r0 /* get next ascii byte */
beql 1f /* if zero: end of string */
movzbl CTABLE(r0),r0 /* and get the r50 byte from the table*/
rsb
1:
tstl (sp)+ /* we're through, get back to where */
/* rad50 was called */
movw r1,(r5) /* but first save the result */
rsb
.align 2
readcom:
.byte 2 /* command packet flag */
.byte 10 /* number of bytes in message */
.byte 2 /* tu read opcode */
.byte 0 /* modifier */
.byte 0 /* unit number */
.byte 0 /* switches */
.word 0 /* sequence number */
/* byte count and block number follow */
ermsg:
.asciz "tuerr\r\n"
end:
/*
* Ascii to rad 50 conversion table,
* stored on the second block on the cassette
*
* NOTE: Always make sure this table ends up
* starting at byte 512!!!!
*/
.align 2
.data 2
.long 0x1d1d1d1d
.long 0x1d1d1d1d
.long 0x1d1d1d1d
.long 0x1d1d1d1d
.long 0x1d1d1d1d
.long 0x1d1d1d1d
.long 0x1d1d1d1d
.long 0x1d1d1d1d
.long 0x1d1d1d00
.long 0x1d1d1d1b
.long 0x1d1d1d1d
.long 0x1d1c1d1d
.long 0x21201f1e
.long 0x25242322
.long 0x1d1d2726
.long 0x1d1d1d1d
.long 0x302011d
.long 0x7060504
.long 0xb0a0908
.long 0xf0e0d0c
.long 0x13121110
.long 0x17161514
.long 0x1d1a1918
.long 0x1d1d1d1d
.long 0x302011d
.long 0x7060504
.long 0xb0a0908
.long 0xf0e0d0c
.long 0x13121110
.long 0x17161514
.long 0x1d1a1918
.long 0x1d1d1d1d
.long 0x1d1d1d1d
.long 0x1d1d1d1d
.long 0x1d1d1d1d
.long 0x1d1d1d1d
.long 0x1d1d1d1d
.long 0x1d1d1d1d
.long 0x1d1d1d1d
.long 0x1d1d1d1d
.long 0x1d1d1d00
.long 0x1d1d1d1b
.long 0x1d1d1d1d
.long 0x1d1c1d1d
.long 0x21201f1e
.long 0x25242322
.long 0x1d1d2726
.long 0x1d1d1d1d
.long 0x302011d
.long 0x7060504
.long 0xb0a0908
.long 0xf0e0d0c
.long 0x13121110
.long 0x17161514
.long 0x1d1a1918
.long 0x1d1d1d1d
.long 0x302011d
.long 0x7060504
.long 0xb0a0908
.long 0xf0e0d0c
.long 0x13121110
.long 0x17161514
.long 0x1d1a1918
.long 0x1d1d1d
.data