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149 lines
3.0 KiB
149 lines
3.0 KiB
;
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;==================================================================================================
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; SIMPLE SERIAL DRIVER
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;==================================================================================================
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;
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; TODO:
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;
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DEVECHO "SSER: IO="
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DEVECHO SSERSTATUS
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DEVECHO "\n"
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;
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;
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;
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SSER_PREINIT:
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;
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; TEST FOR PRESENCE
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;
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XOR A ; CLEAR ACCUM
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LD (SSER_PRESENT),A ; PRESET TO NOT PRESENT
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CALL SSER_DETECT ; CHECK FOR HARDWARE, Z=PRESENT
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RET NZ ; ABORT IF NOT PRESENT
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OR $FF ; PRESENT FLAG
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LD (SSER_PRESENT),A ; STORE IT
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;
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; ADD OURSELVES TO CIO DISPATCH TABLE
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;
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LD D,0 ; PHYSICAL UNIT IS ZERO
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LD E,CIODEV_SSER ; DEVICE TYPE
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LD BC,SSER_FNTBL ; BC := FUNCTION TABLE ADDRESS
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CALL CIO_ADDENT ; ADD ENTRY, A := UNIT ASSIGNED
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;
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XOR A
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RET
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;
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;
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;
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SSER_INIT:
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LD A,(SSER_PRESENT) ; PRESENT FLAG
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OR A ; SET FLAGS
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RET Z ; ABORT IF NOT PRESENT
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CALL NEWLINE
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PRTS("SSER:$")
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PRTS(" IO=0x$") ; FORMATTING
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LD A,SSERSTATUS
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CALL PRTHEXBYTE
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;
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XOR A ; SIGNAL SUCCESS
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RET
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;
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; DRIVER FUNCTION TABLE
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;
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SSER_FNTBL:
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.DW SSER_IN
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.DW SSER_OUT
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.DW SSER_IST
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.DW SSER_OST
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.DW SSER_INITDEV
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.DW SSER_QUERY
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.DW SSER_DEVICE
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#IF (($ - SSER_FNTBL) != (CIO_FNCNT * 2))
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.ECHO "*** INVALID SSER FUNCTION TABLE ***\n"
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#ENDIF
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;
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;
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;
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SSER_IN:
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CALL SSER_IST ; CHECK FOR CHAR PENDING
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JR Z,SSER_IN ; WAIT FOR IT IF NECESSARY
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IN A,(SSERDATA) ; READ THE CHAR
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LD E,A
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RET
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;
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;
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;
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SSER_IST:
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IN A,(SSERSTATUS) ; READ LINE STATUS REGISTER
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#IF (SSERIINV)
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CPL
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#ENDIF
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AND SSERIRDY ; ISOLATE DATA READY
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JP Z,CIO_IDLE ; RETURN VIA IDLE PROCESSING
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OR $FF ; SET A=$FF TO SIGNAL READY
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RET ; RETURN
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;
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;
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;
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SSER_OUT:
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CALL SSER_OST ; CHECK FOR OUTPUT READY
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JR Z,SSER_OUT ; WAIT IF NECESSARY
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LD A,E ; RECOVER THE CHAR TO WRITE
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OUT (SSERDATA),A ; WRITE THE CHAR
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RET
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;
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;
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;
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SSER_OST:
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IN A,(SSERSTATUS) ; READ LINE STATUS REGISTER
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#IF (SSEROINV)
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CPL
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#ENDIF
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AND SSERORDY ; ISOLATE OUTPUT RDY
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JP Z,CIO_IDLE ; RETURN VIA IDLE PROCESSING
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OR $FF ; SET A=$FF TO SIGNAL READY
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RET ; RETURN
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;
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;
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;
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SSER_INITDEV:
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SYSCHKERR(ERR_NOTIMPL)
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RET
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;
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;
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;
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SSER_QUERY:
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LD DE,SSERCFG
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XOR A
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RET
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;
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;
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;
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SSER_DEVICE:
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LD D,CIODEV_SSER ; D := DEVICE TYPE
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LD E,0 ; E := DEVICE NUM, ALWAYS 0
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LD C,$00 ; C := DEVICE TYPE, 0x00 IS RS-232
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LD H,0 ; H := 0, DRIVER HAS NO MODES
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LD L,SSERSTATUS ; L := BASE I/O ADDRESS
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XOR A ; SIGNAL SUCCESS
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RET
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;
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; TEST FOR HARDWARE PRESENCE BY CHECKING THE STATUS PORT. IF IT IS
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; $FF, WE ASSUME NOT PRESENT. THEN READ PORT A DIFFERENT WAY. IF
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; PRESENT PORT SHOULD HAVE SAME VALUE.
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;
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;
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SSER_DETECT:
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IN A,(SSERSTATUS) ; GET DATA PORT VALUE DIRECTLY
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CP $FF ; CHECK FOR $FF
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JR NZ,SSER_DETECT1 ; IF NOT $FF, MAY BE ACTIVE, CONTINUE
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OR A ; SWITCH ZF BACK TO NZ
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RET ; DONE
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SSER_DETECT1:
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LD C,SSERSTATUS ; PORT ADR TO C
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IN B,(C) ; GET DATA PORT VALUE VIA (C)
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CP B ; COMPARE, EQUAL IMPLIES ACTIVE PORT
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RET
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;
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;
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;
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SSER_PRESENT .DB 0 ; FLAG FOR HARDWARE PRESENT
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