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/ Startup code for two-stage bootstrap

/ non-UNIX instructions
mfpi    = 6500^tst
stst    = 170300^tst
mtpi    = 6600^tst
mfpd    = 106500^tst
mtpd    = 106600^tst
spl     = 230
ldfps   = 170100^tst
stfps   = 170200^tst
wait    = 1
rtt     = 6
halt    = 0
reset   = 5
trap    = 104400

.globl  _end
.globl  _main
start:
       reset
       mov     $340,PS
       mov     $140100,sp

/ set kernel I+D to physical 0 and IO page
       clr     r1
       mov     $77406,r2
       mov     $KISA0,r3
       mov     $KISD0,r4
       jsr     pc,setseg
       mov     $IO,-(r3)
       clr     r1
       mov     $KDSA0,r3
       mov     $KDSD0,r4
       jsr     pc,setseg
       mov     $IO,-(r3)

/ set user I+D to physical 64K (words) and IO page
       mov     $4000,r1
       mov     $UISA0,r3
       mov     $UISD0,r4
       jsr     pc,setseg
       mov     $IO,-(r3)
       mov     $4000,r1
       mov     $UDSA0,r3
       mov     $UDSD0,r4
       jsr     pc,setseg
       mov     $IO,-(r3)

/ enable map
       mov     $65,SSR3        / 22-bit map
       bit     $20,SSR3
       beq     1f
       mov     $3,MSCR
1:
       mov     $30340,PS
       inc     SSR0


/ copy program to user I space
       mov     $_end,r0
       asr     r0
       clr     r1
1:
       mov     (r1),-(sp)
       mtpi    (r1)+
       sob     r0,1b


/ continue execution in user space copy
       mov     $140004,sp
       clr     *$KDSA6
       mov     $140340,-(sp)
       mov     $user,-(sp)
       rtt
user:
       mov     $_end+512.,sp
       mov     sp,r5

       jsr     pc,_main

       trap

       br      user

setseg:
       mov     $8,r0
1:
       mov     r1,(r3)+
       add     $200,r1
       mov     r2,(r4)+
       sob     r0,1b
       rts     pc

.globl  _setseg
_setseg:
       mov     2(sp),r1
       mov     r2,-(sp)
       mov     r3,-(sp)
       mov     r4,-(sp)
       mov     $77406,r2
       mov     $KISA0,r3
       mov     $KISD0,r4
       jsr     pc,setseg
       mov     (sp)+,r4
       mov     (sp)+,r3
       mov     (sp)+,r2
       rts     pc

/ clrseg(addr,count)
.globl  _clrseg
_clrseg:
       mov     4(sp),r0
       beq     2f
       asr     r0
       bic     $!77777,r0
       mov     2(sp),r1
1:
       clr     -(sp)
       mtpi    (r1)+
       sob     r0,1b
2:
       rts     pc


/ mtpi(word,addr)
.globl  _mtpi
_mtpi:
       mov     4(sp),r0
       mov     2(sp),-(sp)
       mtpi    (r0)+
       rts     pc

.globl  __rtt
__rtt:
       halt

PS      = 177776
SSR0    = 177572
SSR1    = 177574
SSR2    = 177576
SSR3    = 172516
KISA0   = 172340
KISA1   = 172342
KISA7   = 172356
KISD0   = 172300
KISD7   = 172316
KDSA0   = 172360
KDSA6   = 172374
KDSA7   = 172376
KDSD0   = 172320
KDSD5   = 172332
SISA0   = 172240
SISA1   = 172242
SISD0   = 172200
SISD1   = 172202
UISA0   = 177640
UISD0   = 177600
UDSA0   = 177660
UDSD0   = 177620
MSCR    = 017777746     / 11/70 memory control register
IO      = 177600
SWR     = 177570

.data