SysIII/usr/src/uts/pdp11/up/dzb/subs.s
/*
* Subroutines
*/
.org 3072
seg3:
/*
* KMC initialization
*/
init:
mov 0,brg
mov brg,r13
mov brg,r14
mov brg,csr2
mov IEO,brg
mov brg,csr0
/*
* Initialize the free-buffer list
*/
#define NPQ 3
#define NQE (NPQ*256-((inqueue+3)&~3))/4
/*
* Define the number of 16-byte input buffers
*/
#define NBUF 16*(16-4-NPQ)
mov NPQ,brg
mov brg,r0
mov NBUF-1,brg
mov brg,r1
mov NIL,brg
mov brg,r11
init2:
RELEASE(r0);
mov 16,brg
add brg,r0
adc r0
dec r1
brc init2
/*
* Initialize the list of available queue entries
*/
mov NIL,brg
mov brg,r12
mov (inqueue+3)&~3,brg
mov brg,r0
mov NQE-1,brg
mov brg,r1
init4:
FREEQ(r0)
mov 4,brg
add brg,r0
adc r0
dec r1
brc init4
/*
* Initialize LTE queue pointers
*/
mov 3,brg
mov brg,r8
init6:
mov %dzst,brg
add brg,r8,%mar
mov 7,r7|mar
init8:
mov mem,r10
mov OUTBUF,brg
add brg,r10,mar
mov NIL,mem|mar++
mov NIL,mem|mar++
mov NIL,mem
dec r7,r7|mar
brc init8
dec r8
brc init6
/*
* Return to caller
*/
RETURN
/*
* Carrier-on status check--executed once every 12.8 msec for each DZ
*/
mdmcheck:
/*
* If the 12.8 millisecond timer hasn't expired yet
* then go to disp
*/
mov clock2,mar
mov mem,r0
dec r0,mem
brc dispret3
/*
* Set up a unibus request for the current value of MSR
*/
mov csrget,mar
mov mem,r2|mar++
mov mem,r1|mar++
mov mem,r0
mov 6,brg
add brg,r2,brg
mov brg,ial
adc r1,brg
mov brg,iah
adc r0
mov 3,brg
and brg,r0
asl r0
asl r0
mov NRQ,brg
or brg,r0,npr
/*
* Wait for the unibus transfer to complete.
* If an error occurs then go to buserr3.
*/
BUSWAIT(buserr3)
/*
* Get the previous value of the carrier-on status indicators
* and save the new value. If the new value is the same as the
* previous value then go to disp
*/
mov costatus,mar
mov mem,r2
mov idh,mem
addn mem,r2,-
brz dispret3
/*
* Initialize regs for loop which follows
*/
mov 0,brg
mov brg,r7
mov 1,r1
/*
* Set a bit in r2 for each line with changed status
*/
xor mem,r2
mov mem,r3
/*
* Step through all lines for this DZ.
*
* For each line with changed status, set the carrier-on
* flag on or off as appropriate
*/
mdmchk2:
mov r1,brg
orn brg,r2,-
brz 1f
br 2f
1:
mov r7,mar
mov mem,r10
mov FLAGS,brg
add brg,r10,mar
mov mem,r0
mov r1,brg
orn brg,r3,-
brz 1f
mov ~CARR_ON,brg
and brg,r0,mem
br 2f
1:
mov CARR_ON,brg
or brg,r0,mem
2:
asl r1
inc r7
mov 7,brg
addn brg,r7,-
brc 1f
br mdmchk2
1:
/*
* If a carrier-on change report has already been requested for this DZ
* then go to disp
*/
mov status,mar
mov mem,r2
mov 1<<2,brg
orn brg,r2,-
brz dispret3
mov 1<<2,brg
or brg,r2,mem
/*
* Insert the page for the current DZ at the end of the
* coc-report-needed queue
*/
mov coclink,mar
mov NIL,mem
mov tailcocq,mar
mov %tailcocq,%mar
mov mem,r0
brz 1f
mov r8,mem
mov %dzst,brg
add brg,r0,%mar
mov coclink,mar
mov r8,mem
br 2f
1:
mov headcocq,mar
mov r8,mem|mar++
mov r8,mem
2:
/*
* Set the global flag which indicates that a
* carrier-on change report has been requested
*/
mov CHKCOCQ,brg
or brg,r14
/*
* Go to disp
*/
br .
br dispret3
/*
* The 50-microsecond hardware timer has expired
*/
tick:
/*
* Reset the 50-microsecond timer
*/
mov nprx,r0
mov ~(BRQ|ACLO|(3<<2)),brg
and brg,r0
mov PCLK,brg
or brg,r0,nprx
/*
* The effect of the following code is to schedule a
* csr check for a different DZ every 50(?) microseconds.
* Since there are four possible DZ's, each DZ gets scheduled
* for a csr check every 200 microseconds. This is approximately
* a factor of five better than we need for 9600 baud (one character
* every 1042 microseconds).
*/
/*
* Increment r15.
*/
inc r15
/*
* Set the DZ number from bits 1-0 of r15.
*/
mov 3,brg
and brg,r15,brg
mov brg,r8
/*
* Set page register to page for this DZ
*/
mov %dzst,brg
add brg,r8,%mar
/*
* If a base-in command has not been received yet for this DZ
* then go to disp
*/
mov status,mar
mov mem,brg
br7 1f
br dispret3
1:
/*
* If a csr check has already been requested for this DZ
* then go to delaycheck
*/
br0 delaycheck
/*
* Set the bit which indicates that a csr check has already
* been scheduled
*/
mov 1<<0,r1
or mem,r1,mem
/*
* Insert the page for the current DZ at the end of the
* csr-check-needed queue
*/
mov csrlink,mar
mov NIL,mem
mov tailcsrq,mar
mov %tailcsrq,%mar
mov mem,r0
brz 1f
mov r8,mem
mov %dzst,brg
add brg,r0,%mar
mov csrlink,mar
mov r8,mem
br 2f
1:
mov headcsrq,mar
mov r8,mem|mar++
mov r8,mem
2:
/*
* Set global flag to indicate that a csr check has been requested
*/
mov CHKCSRQ,brg
or brg,r14
delaycheck:
/*
* Set page register to page for this DZ
*/
mov %dzst,brg
add brg,r8,%mar
/*
* Decrement the 16.7 msec timer. If the result is
* non-negative then go to mdmcheck
*/
mov clock1,mar
mov mem,r0
dec r0,mem
brc dispret3 /* *** temp for testing *** */
/* brc mdmcheck */
/*
* Reset the 16.7 msec timer
*/
mov 50,mem
/*
* The 16.7 msec timer has expired. Therefore we need to decrement
* the count field for each lte which is currently in the twait
* state (delaying)
*/
/*
* Initialize registers for loop which follows
*/
mov 5,r5
mov 7,r7|mar
/*
* The following loop is executed once for each lte
* in the page for the selected DZ.
*
* If we find a line which is in the twait state
* then we decrement the count field of the lte.
* If the result is negative then we put the line
* back into state 1 and enable the line.
*/
delaych1:
/*
* Get the address of the lte
*
* If state == 5 (twait) then go to delaych3
*
* Note that the following code assumes that STATE is the
* first cell in the lte and that the memory-address
* register (mar) has already been loaded from r7
*/
mov mem,r10|mar
addn mem,r5,-
brz delaych3
/*
* Test for end of loop
*/
delaych2:
/*
* Decrement the current entry number. If the result is
* non-negative then go to delaych1
*/
dec r7,r7|mar
brc delaych1
/*
* Go to delaych4
*/
br delaych4
/*
* We get here when we find a line with STATE == 5 (twait)
*/
delaych3:
/*
* Decrement the count field of the lte. If the result is
* non-negative then go to delaych2
*/
mov COUNT,brg
add brg,r10,mar
mov mem,r0
dec r0,mem
brc delaych2
/*
* The time has elapsed, if a break was being transmitted call ubreak
*/
mov FLAGS1,brg
add brg,r10,mar
mov mem,r0
mov OUTBRK,brg
orn brg,r0,-
brz 1f
br 2f
1:
/*
* Turn off treak bit
*/
CALL(ubreak)
mov %dzst,brg
add brg,r8,%mar
br delaych2
2:
/*
* Continue sending data.
*/
/*
* Set state = 1 (sending normal data)
*/
mov STATE,brg
add brg,r10,mar
mov 1,mem
/*
* Turn on the enable bit for this line
*/
CALL(enable)
mov %dzst,brg
add brg,r8,%mar
/*
* Go to delaych2
*/
br delaych2
/*
* End of above loop
*/
delaych4:
/*
* Input time-out test
*
* Loop through all eight lines for this DZ. For each line with a non-empty
* input queue, if the timer has expired then put the line on the
* input-ready queue
*/
mov 7,r7
1:
mov r7,mar
mov mem,r10
/*
* See if timer is active
*/
mov FLAGS1,brg
add brg,r10,mar
mov mem,r0
mov TIMACT,brg
orn brg,r0,-
brz 2f
br 3f
2:
/*
* Timer is active, decrement ITIME
*/
mov ITIME,brg
add brg,r10,mar
mov mem,r0
dec r0,mem
brc 3f
/*
* Timer has expired, queue input and reset TIMER
*/
mov FLAGS1,brg
add brg,r10,mar
mov mem,r0
mov ~TIMACT,brg
and brg,r0,mem
CALL(queue)
mov %dzst,brg
add brg,r8,%mar
3:
dec r7
brc 1b
/*
* Return to dispatcher
*/
br dispret3
/*
* The following code checks for output character completions
* and input data ready in the silo
*/
csrcheck:
/*
* If the check-CSR queue is empty then error
*/
mov headcsrq,mar
mov %headcsrq,%mar
mov mem,r8
brz csrcout
mov %dzst,brg
add brg,r8,%mar
/*
* Set up a unibus request for the current value of CSR
*/
mov csrget,mar
mov mem,ial|mar++
mov mem,iah|mar++
mov mem,r0
asl r0
asl r0
mov NRQ,brg
or brg,r0,npr
/*
* Wait for the unibus transfer to complete.
* If an error occurs then go to buserr0.
*/
BUSWAIT(buserr3)
/*
* If there is an input character available then go to csrchk2
*/
mov idl,brg
br7 csrchk2
/*
* If there is an output data request then go to csrchk4
*/
mov idh,brg
br7 csrchk4
/*
* Clear the bit that indicates that a csr check has been scheduled for this page
*/
mov status,mar
mov ~(1<<0),brg
mov brg,r0
and mem,r0,mem
/*
* Remove the current DZ from the csr-check-needed queue;
* if the queue is empty then clear the CHKCSRQ bit in r14
*/
mov csrlink,mar
mov mem,brg
mov %headcsrq,%mar
mov headcsrq,mar
mov brg,mem|mar++
brz 1f
br 2f
1:
mov brg,mem
csrcout:
mov ~CHKCSRQ,brg
and brg,r14
2:
/*
* Go to disp
*/
br dispret3
/*
* Input data available--jump to input segment
*/
csrchk2:
mov %inchar,brg
mov brg,pcr
jmp inchar
/*
* Output data request--jump to output segment
*/
csrchk4:
mov %outreq,brg
mov brg,pcr
jmp outreq
dispret3:
mov %disp,brg
mov brg,pcr
jmp disp
/*
* The following code queues and error report
*/
erqueue:
/*
* If an error has already been queued for this dz just return
*/
mov %dzst,brg
add brg,r8,%mar
mov status,mar
mov mem,r0
mov 1<<5,brg
orn brg,r0,-
brz 2f
or brg,r0,mem
/*
* Increment the error counter
*/
mov errcnt,mar
mov mem,r0
inc r0,mem
/*
* Get the driver's idea of the DZ number and combine it with the line
* number to get the minor device number
*/
mov dznr,mar
mov mem,r0
asl r0
asl r0
asl r0
mov 07,brg
and brg,r7,brg
or brg,r0
/*
* Queue an error for this line
*/
GETQ(r4,queuerr3)
mov NIL,mem|mar++
/*
* Put dznr<<3|line number in second byte
*/
mov r0,mem|mar++
/*
* Put error number into third byte
*/
mov r1,mem|mar++
/*
* Save r8
*/
mov r8,mem
mov %tailerrq,%mar
mov tailerrq,mar
mov mem,r0
brz 1f
mov r4,mem
mov 03,brg
and brg,r0,%mar
mov ~03,brg
and brg,r0,mar
mov r4,mem
br 2f
1:
mov headerrq,mar
mov r4,mem|mar++
mov r4,mem
/*
* Indicat an error queued
*/
2:
mov CHKERRQ,brg
or brg,r14
RETURN
/*
* Unibus error
*/
buserr3:
/*
* Clear the non-existent memory bit
*/
mov nprx,r0
mov ~(BRQ|ACLO|NEM),brg
and brg,r0,nprx
ERROR(BUSERR3)
br dispret3
queuerr3:
/*
* No queue entries to queue an error, tough
*/
br .
endseg3: