~ National ~ Semiconductor - Al Kossow's Bitsavers

holdloop: nop
#
br hold loop
#
#
#****************************** INTERRUPT HANDLER ******************************
isr:
#
~ave [rO,rl,r2,r3,r4,r5,r6,r7]
movb lir,rO
#RO- contains llr
cmpb rO,$OxOc6 #
beq ISlnt
#Llne status lnterrupt
cmpb rO,$OxOc4 #
beq rdal
#Recelver interrupt
cmpb rO,$OxOcc #
beq rtmout
cmpb rO,$OxOc2
#Rec timeout interrupt
#
beq threi
#THRE interrupt
cmpb rO,$OxOcO #
beq mSlnt
#Modem status interrupt
#
#
#************************** INVALID INTERRUPT ROUTINE **************************
save [rO,rl,r2,r3]
movd $4,rO
addr message2,rl
movd $21,r2
movd $O,r3
svc
restore [rO,rl,r2,r3]
#
•
#
#
#
#
#
•#
#
jump stop
#Restore all registers
#
#
#********************* RECEIVER TIMEOUT INTERRUPT ROUTINE ************.*********
#
rtmout:
jump rdal
#
#*************************** RECEIVER INTERRUPT ROUTINE ************************
#
#Th1s portion of the program is reached by a positive test for the received data
#available interrupt. Once in this routine each byte 1s removed from the FIFO,
#placed 1n a des1gnated statlc base memory location and the LSR is tested to see
#If tne data ready (DR) blt 18 etill set. Data is removed from the FIFO and
.placed in memory untll the DR bit is no longer set. Tne data sent will be
#compared to known data, located in another deslgnated static base location, by
#calling the compare subroutine.
rdai:
rdrbr:
continue:
movb $O,mcr
addr rbuf(sb),r4
movd rbufoff,r6
movb rxd,O(r4)[r6:b]
cmpb $OxOO,O(r4)[r6:b]
addqw l,r6
addqw l, rbufoff
bne continue
movw SO,r6
movw $O,rbufoff
movb lsr,r3
andb $Ol,r3
cmpb SOl,r3
#Disable RTS; stop transmission
#r4 contains rbuf base address
#Put rbuf offset runner into r6
#Store a byte in the receiver buffer
#Is 1t the last character
#Increment offset ptr.
#Track r6
#
#Reset pointer offset
#Reset rbufoff
#Read lsr
#Mask all but bit 0
•
TL/C/9313-16
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