.TITLE IMP PERM ROUTINES ; ; R.D. EAGER ; UNIVERSITY OF KENT AT CANTERBURY ; MARCH 1976 ; .SBTTL MANIFEST CONSTANTS ; ; ASSEMBLY OPTIONS ; ; ; THE FOLLOWING SYMBOL SHOULD BE DEFINED IF THE TARGET ; MACHINE HAS THE EXTENDED INSTRUCTION SET (EIS) OPTION ; ; EIS = 1 ; .ENABL ABS ;ELIMINATES LINKING, AND THUS THE DOS HEADER ; ; REGISTER NAMES ; R0 = %0 R1 = %1 R2 = %2 R3 = %3 R4 = %4 R5 = %5 SP = %6 PC = %7 GLA = %4 ;GLOBAL LINKAGE AREA POINTER LNB = %5 ;LOCAL NAMEBASE POINTER ; ; CHARACTER CODES ; LF = 12 CR = 15 SPACE = 40 ; ; TRAP CODES ; MONITOR = 0 ;MONITOR ENTRY RDSYM = 1 ;READSYMBOL -> R0 NXTSYM = 2 ;NEXTSYMBOL -> R0 PRSYM = 3 ;R0 -> PRINTSYMBOL SEL.IN = 4 ;SELECTINPUT(R0) SEL.OUT = 5 ;SELECTOUTPUT(R0) ILLEGAL = 6 ;TRAPS ABOVE THIS ARE ILLEGAL ; ; PROGRAM TERMINATION CODES ; ABORT = -1 ;(-VE). GIVES 'ABORT' MESSAGE NORMAL = 0 ;NO MESSAGE EXB = 1 ;STACK OVERFLOW SID = 2 ;SYMBOL IN DATA OFAIL = 3 ;CHANNEL OPEN FAILURE NOTRAP = 4 ;UNKNOWN TRAP CODE NSL = 5 ;NON-EXISTENT SWITCH LABEL EOF = 8. ;READ PAST END-OF-FILE ILLIO = 9. ;MISUSE OF I/O SYSTEM INVSEL = 10. ;INVALID CHANNEL SELECTION ; ; OFFSETS OF ITEMS IN GLOBAL LINKAGE AREA ; PROG = 2 ;PROGRAM BASE LIMIT = 4 ;STACK LIMIT .SBTTL ENTRY VECTOR ; .ASECT .=-2 ; TOP: LAST-TOP/2 ENTER1/2 ENTER2/2 ENTER3/2 ENTER4/2 ENTER5/2 EXIT1/2 EXIT2/2 EXIT3/2 EXIT4/2 EXIT5/2 TEXIT1/2 TEXIT2/2 TEXIT3/2 TEXIT4/2 TEXIT5/2 RSHIFT/2 SJUMP/2 MON/2 STOP/2 RMOVE/2 RCLEAR/2 0 PXOR/2 PMUL/2 PDIV/2 LSHIFT/2 0 0 0 0 0 ; ; PERM ROUTINES ; 0 ;31 - DISPLAY 0 ;32 - PROMPT SELOUT/2 ;33 - SELECT OUTPUT SELIN/2 ;34 - SELECT INPUT 0 ;35 - MATCH 0 ;36 - FROM STRING 0 ;37 - CHARNO 0 ;38 - TO STRING 0 ;39 - LENGTH READ/2 ;40 - READ SSYM/2 ;41 - SKIP SYMBOL RSYM/2 ;42 - READ SYMBOL NSYM/2 ;43 - NEXT SYMBOL SPACS/2 ;44 - SPACES SPAC/2 ;45 - SPACE NEWLS/2 ;46 - NEWLINES NEWL/2 ;47 - NEWLINE PSTR/2 ;48 - PRINT STRING PSYM/2 ;49 - PRINT SYMBOL WRIT/2 ;50 - WRITE 0 ;51 - CLOSE INPUT 0 ;52 - CLOSE OUTPUT SVC/2 ;53 - SVC (EMT CALL) INT/2 ;54 - INTEGER INT/2 ;55 - BYTEINTEGER INT/2 ;56 - ADDR ACC/2 ;57 - ACC LAST: .SBTTL LOGICAL SHIFT ROUTINES ; RSHIFT: ENDB-RSHIFT-2/2 MOV (SP)+,R3 ;RETURN LINK MOV (SP)+,R0 ;NUMBER OF PLACES TO SHIFT MOV (SP)+,R1 ;WORD TO BE SHIFTED RS1: DEC R0 BLT RS2 CLC ROR R1 BR RS1 RS2: MOV R3,PC ENDB: ; LSHIFT: ENDLSH-LSHIFT-2/2 MOV (SP)+,R3 ;RETURN LINK MOV (SP)+,R0 ;NUMBER OF PLACES TO SHIFT MOV (SP)+,R1 ;WORD TO BE SHIFTED LS1: DEC R0 BLT LS2 ASL R1 BR LS1 LS2: MOV R3,PC ENDLSH: .SBTTL SWITCH HANDLER ; ; ON ENTRY :- ; R1 = SWITCH INDEX ; R0 = DISPLACEMENT OF SWITCH VECTOR WITHIN GLA ; ; SWITCH VECTOR IS OF THE FORM :- ; , , , , ....... , ; SJUMP: ENDC-SJUMP-2/2 ADD GLA,R0 CMP R1,(R0)+ ;SWITCH INDEX OVER UPPER BOUND? BGT SWERR ;YES - ERROR CMP R1,(R0) ;SWITCH INDEX BELOW LOWER BOUND? BLT SWERR ;YES - ERROR SUB (R0)+,R1 ;NORMALISE SWITCH INDEX RELATIVE TO ZERO ASL R1 ;CONVERT TO A BYTE OFFSET ADD R1,R0 ;CONSTRUCT INDEX INTO SWITCH VECTOR MOV (R0),R2 ;GET NEW PC VALUE FROM SWITCH VECTOR BEQ SW1 ;DROP THROUGH SWITCH IF ENTRY IS ZERO ADD PROG(GLA),R2 ;RELOCATE PC VALUE RELATIVE TO PROGRAM BASE MOV R2,(SP) ;PUT NEW PC VALUE ON STACK FOR RTS SW1: RTS PC ;GO TO SELECTED CODE OR DROP THROUGH SWERR: MOV #NSL,R0 ;SWITCH VALUE OUT OF RANGE ... TRAP MONITOR ;... SO GIVE SUITABLE TERMINATION CODE ENDC: .SBTTL PROGRAM TERMINATION ROUTINES ; ; ; %STOP OPERATION ; STOP: ENDE-STOP-2/2 CLR R0 ;CODE FOR SUCCESSFUL TERMINATION IS ZERO TRAP MONITOR ENDE: ; ; %MONITOR OPERATION ; MON: ENDD-MON-2/2 TRAP MONITOR ;TERMINATION CODE IS IN R0 ON ENTRY ENDD: .SBTTL I/O CHANNEL SELECTION ROUTINES ; ; %ROUTINE SELECT INPUT(%INTEGER N) ; SELIN: ENDJ-SELIN-2/2 MOV 2(SP),R0 ;CHANNEL NUMBER MOV (SP)+,(SP) TRAP SEL.IN RTS PC ENDJ: ; ; %ROUTINE SELECT OUTPUT(%INTEGER N) ; SELOUT: ENDK-SELOUT-2/2 MOV 2(SP),R0 ;CHANNEL NUMBER MOV (SP)+,(SP) TRAP SEL.OUT RTS PC ENDK: .SBTTL SYMBOL I/O ROUTINES ; ; %ROUTINE READ SYMBOL(%INTEGERNAME N) ; RSYM: ENDG-RSYM-2/2 TRAP RDSYM MOV (SP)+,R1 MOV R0,@(SP)+ MOV R1,PC ENDG: ; ; %ROUTINE PRINT SYMBOL(%INTEGER N) ; PSYM: ENDH-PSYM-2/2 MOV (SP)+,R1 MOV (SP)+,R0 TRAP PRSYM MOV R1,PC ENDH: ; ; %INTEGERFN NEXT SYMBOL ; NSYM: ENDI-NSYM-2/2 TRAP NXTSYM MOV R0,R1 RTS PC ENDI: ; ; %ROUTINE SKIP SYMBOL ; SSYM: ENDS-SSYM-2/2 TRAP RDSYM RTS PC ENDS: .SBTTL SPACE AND NEWLINE OUTPUT ROUTINES ; ; %ROUTINE SPACE ; SPAC: ENDT-SPAC-2/2 MOV #SPACE,R0 TRAP PRSYM RTS PC ENDT: ; ; %ROUTINE NEWLINE ; NEWL: ENDU-NEWL-2/2 MOV #CR,R0 ;ADD A CARRIAGE RETURN TRAP PRSYM MOV #LF,R0 TRAP PRSYM RTS PC ENDU: ; ; %ROUTINE SPACES(%INTEGER N) ; SPACS: ENDV-SPACS-2/2 MOV 2(SP),R2 ;NUMBER OF SPACES TO OUTPUT MOV (SP)+,(SP) SP1: DEC R2 BLT SP2 MOV #SPACE,R0 TRAP PRSYM BR SP1 SP2: RTS PC ENDV: ; ; %ROUTINE NEWLINE(%INTEGER N) ; NEWLS: ENDW-NEWLS-2/2 MOV 2(SP),R2 ;NUMBER OF NEWLINES TO OUTPUT MOV (SP)+,(SP) NL1: DEC R2 BLT NL2 MOV #CR,R0 ;ADD A CARRIAGE RETURN TRAP PRSYM MOV #LF,R0 TRAP PRSYM BR NL1 NL2: RTS PC ENDW: .SBTTL MOVE BLOCK AND CLEAR BLOCK (OF STORE) ; ; BLOCK MOVE ROUTINE ; ON ENTRY :- ; R0 = LENGTH OF BLOCK (IN WORDS) ; R1 = START ADDRESS OF DESTINATION AREA ; R2 = START ADDRESS OF SOURCE AREA ; RMOVE: ENDL-RMOVE-2/2 RM1: MOV (R2)+,(R1)+ DEC R0 BGT RM1 RTS PC ENDL: ; ; CLEAR BLOCK ROUTINE ; ON ENTRY :- ; R0 = LENGTH OF BLOCK (IN WORDS) ; R1 = START ADDRESS OF BLOCK ; RCLEAR: ENDM-RCLEAR-2/2 RC1: CLR (R1)+ DEC R0 BGT RC1 RTS PC ENDM: .SBTTL ROUTINE ENTRY AND EXIT CODE ; ENTER1: END1-ENTER1-2/2 TST (SP)+ ;REMOVE UNWANTED PREVIOUS R0 VALUE MOV (SP),-(LNB) ;SAVE RETURN LINK MOV -(GLA),-(LNB) MOV (R0)+,-(LNB) ADD SP,(LNB) MOV LNB,(SP) MOV SP,LNB MOV LNB,(GLA)+ ADD (R0)+,SP CMP SP,LIMIT(GLA) ;STACK OVERFLOW? BLOS E1EXB ;YES MOV R0,PC ;NO - ENTER ROUTINE E1EXB: MOV LNB,SP ;ENSURE ERROR ROUTINES HAVE A STACK MOV #EXB,R0 TRAP MONITOR ;FORCE TERMINATION END1: ; EXIT1: END2-EXIT1-2/2 MOV (LNB),LNB MOV (LNB)+,SP MOV (LNB)+,-2(GLA) MOV (LNB)+,PC END2: ; ENTER2: END3-ENTER2-2/2 TST (SP)+ ;REMOVE UNWANTED PREVIOUS R0 VALUE MOV (SP),-(LNB) ;SAVE RETURN LINK MOV -4(GLA),-(LNB) MOV (R0)+,-(LNB) ADD SP,(LNB) MOV LNB,(SP) MOV SP,LNB MOV LNB,-4(GLA) ADD (R0)+,SP CMP SP,LIMIT(GLA) ;STACK OVERFLOW? BLOS E2EXB ;YES MOV R0,PC ;NO - ENTER ROUTINE E2EXB: MOV LNB,SP ;ENSURE ERROR ROUTINES HAVE A STACK MOV #EXB,R0 TRAP MONITOR ;FORCE TERMINATION END3: ; EXIT2: END4-EXIT2-2/2 MOV (LNB),LNB MOV (LNB)+,SP MOV (LNB)+,-4(GLA) MOV (LNB)+,PC END4: ; ENTER3: END5-ENTER3-2/2 TST (SP)+ ;REMOVE UNWANTED PREVIOUS R0 VALUE MOV (SP),-(LNB) ;SAVE RETURN LINK MOV -6(GLA),-(LNB) MOV (R0)+,-(LNB) ADD SP,(LNB) MOV LNB,(SP) MOV SP,LNB MOV LNB,-6(GLA) ADD (R0)+,SP CMP SP,LIMIT(GLA) ;STACK OVERFLOW? BLOS E3EXB ;YES MOV R0,PC ;NO - ENTER ROUTINE E3EXB: MOV LNB,SP ;ENSURE ERROR ROUTINES HAVE A STACK MOV #EXB,R0 TRAP MONITOR ;FORCE TERMINATION END5: ; EXIT3: END6-EXIT3-2/2 MOV (LNB),LNB MOV (LNB)+,SP MOV (LNB)+,-6(GLA) MOV (LNB)+,PC END6: ; ENTER4: END7-ENTER4-2/2 TST (SP)+ ;REMOVE UNWANTED PREVIOUS R0 VALUE MOV (SP),-(LNB) ;SAVE RETURN LINK MOV -10(GLA),-(LNB) MOV (R0)+,-(LNB) ADD SP,(LNB) MOV LNB,(SP) MOV SP,LNB MOV LNB,-10(GLA) ADD (R0)+,SP CMP SP,LIMIT(GLA) ;STACK OVERFLOW? BLOS E4EXB ;YES MOV R0,PC ;NO - ENTER ROUTINE E4EXB: MOV LNB,SP ;ENSURE ERROR ROUTINES HAVE A STACK MOV #EXB,R0 TRAP MONITOR ;FORCE TERMINATION END7: ; EXIT4: END8-EXIT4-2/2 MOV (LNB),LNB MOV (LNB)+,SP MOV (LNB)+,-10(GLA) MOV (LNB)+,PC END8: ; ENTER5: END9-ENTER5-2/2 TST (SP)+ ;REMOVE UNWANTED PREVIOUS R0 VALUE MOV (SP),-(LNB) ;SAVE RETURN LINK MOV -12(GLA),-(LNB) MOV (R0)+,-(LNB) ADD SP,(LNB) MOV LNB,(SP) MOV SP,LNB MOV LNB,-12(GLA) ADD (R0)+,SP CMP SP,LIMIT(GLA) ;STACK OVERFLOW? BLOS E5EXB ;YES MOV R0,PC ;NO - ENTER ROUTINE E5EXB: MOV LNB,SP ;ENSURE ERROR ROUTINES HAVE A STACK MOV #EXB,R0 TRAP MONITOR ;FORCE TERMINATION END9: ; EXIT5: ENDA-EXIT5-2/2 MOV (LNB),LNB MOV (LNB)+,SP MOV (LNB)+,-12(GLA) MOV (LNB)+,PC ENDA: .SBTTL EXIT ROUTINES ; TEXIT1: ENDN-TEXIT1-2/2 MOV (LNB),LNB MOV (LNB)+,SP MOV (LNB)+,-2(GLA) SEZ JMP @(LNB)+ ENDN: ; TEXIT2: ENDO-TEXIT2-2/2 MOV (LNB),LNB MOV (LNB)+,SP MOV (LNB)+,-4(GLA) SEZ JMP @(LNB)+ ENDO: ; TEXIT3: ENDP-TEXIT3-2/2 MOV (LNB),LNB MOV (LNB)+,SP MOV (LNB)+,-6(GLA) SEZ JMP @(LNB)+ ENDP: ; TEXIT4: ENDQ-TEXIT4-2/2 MOV (LNB),LNB MOV (LNB)+,SP MOV (LNB)+,-10(GLA) SEZ JMP @(LNB)+ ENDQ: ; TEXIT5: ENDR-TEXIT5-2/2 MOV (LNB),LNB MOV (LNB)+,SP MOV (LNB)+,-12(GLA) SEZ JMP @(LNB)+ ENDR: .SBTTL EXCLUSIVE 'OR' OPERATION ; PXOR: ENDXOR-PXOR-2/2 MOV (SP)+,R3 ;RETURN ADDRESS MOV (SP)+,R0 ;B MOV (SP)+,R1 ;A MOV R0,R2 BIC R1,R2 ;B & \A BIC R0,R1 ;\B & A BIS R2,R1 ;(B & \A) ! (\B & A) MOV R3,PC ENDXOR: .SBTTL MULTIPLY AND DIVIDE OPERATIONS ; PMUL: ENDMUL-PMUL-2/2 MOV (SP)+,R1 ;RETURN ADDRESS MOV (SP)+,R0 ;B MOV (SP),R2 ;A MOV R1,(SP) ;SAVE RETURN ADDRESS FOR 'RTS' MOV #20,R3 ;LOOP COUNT CLR R1 ;INITIALISE RESULT MUL1: ROR R0 BCC MUL2 ;-> IF CARRY = 0 ADD R2,R1 ;ACCUMULATE RESULT MUL2: ASL R2 DEC R3 BGT MUL1 RTS PC ENDMUL: ; PDIV: ENDDIV-PDIV-2/2 MOV (SP)+,R1 ;RETURN ADDRESS MOV #1,R0 ;SIGN OF EVENTUAL RESULT MOV (SP)+,R3 ;B BGE DIV1 NEG R3 ;OBTAIN ABSOLUTE VALUE OF B NEG R0 ;AND SET SIGN INDICATION DIV1: MOV (SP),R2 ;A BGE DIV2 NEG R2 ;OBTAIN ABSOLUTE VALUE OF A NEG R0 ;AND SET SIGN INDICATION DIV2: MOV R1,(SP) ;SAVE RETURN ADDRESS FOR 'RTS' MOV R0,-(SP) ;SIGN OF RESULT MOV #20,-(SP) ;LOOP COUNT CLR R0 ;REMAINDER CLR R1 ;RESULT DIV3: ASL R0 ASL R1 ROL R2 ADC R0 CMP R0,R3 BLT DIV4 INC R1 SUB R3,R0 DIV4: DEC (SP) BNE DIV3 TST (SP)+ ;REMOVE COUNT (NOW ZERO) TST (SP)+ ;EXAMINE SIGN (AND REMOVE) BGE DIV5 NEG R1 ;CHANGE SIGN OF RESULT IF NECESSARY DIV5: RTS PC ENDDIV: .SBTTL %ROUTINE PRINTSTRING(%STRING S) ; PSTR: ENDPST-PSTR-2/2 MOV (SP)+,R3 ;RETURN ADDRESS MOV (SP)+,R1 ;ADDRESS OF STRING MOVB (R1)+,R2 ;STRING LENGTH BIC #177400,R2 ;REMOVE RUBBISH BEQ PST3 ;CASE OF NULL STRING PST1: MOVB (R1)+,R0 ;GET NEXT CHARACTER FROM STRING CMPB #LF,R0 ;IS IT A LINEFEED? BNE PST2 ;NO - JUST PRINT IT MOV #CR,R0 ;YES - ADD A CARRIAGE RETURN TRAP PRSYM MOV #LF,R0 ;NOW THE LINEFEED ITSELF PST2: TRAP PRSYM DEC R2 BNE PST1 PST3: MOV R3,PC ;RETURN ENDPST: .SBTTL %ROUTINE READ(%NAME A) ; READ: ENDRD-READ-2/2 READ1: TRAP NXTSYM CMPB #CR,R0 BEQ READ2 ;IGNORE CARRIAGE RETURN CMPB #LF,R0 BEQ READ2 ;AND LINEFEED CMPB #SPACE,R0 BNE READ3 READ2: TRAP RDSYM ;SKIP THAT CHARACTER BR READ1 ;AND TRY AGAIN READ3: CLR -(SP) ;CLEAR MINUS FLAG CLR R3 ;CLEAR 'FOUND DIGIT' FLAG CLR R1 CMPB #'-,R0 ;MINUS SIGN? BNE READ5 ;NO COM (SP) ;YES - SET MINUS FLAG READ4: TRAP RDSYM TRAP NXTSYM READ5: CMPB #'0,R0 BGT READ6 ;BRANCH IF NOT DIGIT CMPB #'9,R0 BLT READ6 ;BRANCH IF NOT DIGIT SUB #'0,R0 INC R3 ;REMEMBER AT LEAST ONE DIGIT WAS FOUND MOV R1,R2 ASL R2 ASL R2 ADD R2,R1 ASL R1 ADD R0,R1 BR READ4 READ6: TST R3 ;FOUND AT LEAST ONE DIGIT? BNE READ7 ;BRANCH IF YES MOV #SID,R0 TRAP MONITOR ;ERROR - SYMBOL IN DATA READ7: TST (SP)+ BEQ READ8 NEG R1 READ8: MOV (SP)+,R3 MOV R1,@(SP)+ MOV R3,PC ENDRD: .SBTTL %ROUTINE WRITE(%INTEGER I, J) ; WRIT: ENDWRIT-WRIT-2/2 MOV 2(SP),R3 ;NUMBER OF PLACES MOV 4(SP),R1 ;VALUE TO PRINT BGE WRIT0 ;< 0? NEG R1 ;MAKE IT POSITIVE WRIT0: MOV SP,R2 ;REFERENCE POINTER WRIT1: .IF DF EIS CLR R0 ;EXTEND TO 32 BITS DIV #12,R0 ; //10 MOV R0,-(SP) ;REMAINDER AND QUOTIENT ARE REVERSED MOV R1,R0 MOV (SP)+,R1 .IFF MOV R2,-(SP) MOV R3,-(SP) MOV R1,-(SP) MOV #12,-(SP) JSR SP,#30 ;SPECIAL - FILLED IN BY CODE GENERATOR MOV (SP)+,R3 MOV (SP)+,R2 .ENDC ADD #'0,R0 MOV R0,-(SP) ;TOSTRING IT DEC R3 ;REMOVE ONE PLACE TST R1 ;= 0? BNE WRIT1 ;NO, => MORE LEFT MOV #SPACE,-(SP) ;NULL SIGN TST 4(R2) BGE WRIT2 MOV #'-,(SP) ;IT'S NEGATIVE WRIT2: DEC R3 BLT WRIT3 ;ENOUGH PLACES MOV #SPACE,-(SP) BR WRIT2 WRIT3: MOV (SP)+,R0 TRAP PRSYM CMP SP,R2 ;BACK TO REFERENCE YET? BNE WRIT3 ;NO MOV (SP)+,(SP) MOV (SP)+,(SP) RTS PC ENDWRIT: .SBTTL SVC, MAPS, ADDR, ACC AND RECORD ; ; %ROUTINE SVC(%INTEGER EP, %BYTEINTEGERNAME R0, R1) ; SVC: ENDSVC-SVC-2/2 MOV (SP)+,R3 ;RETURN ADDRESS MOV (SP)+,R1 ;R1 VALUE MOV (SP)+,R0 ;R0 VALUE MOVB (SP)+,6(GLA) ;EMT CODE (EMT 0 IN GLA) JSR PC,6(GLA) ;GO DO THE EMT MOV R3,PC ;RETURN ENDSVC: ; ; %INTEGERMAP INTEGER(%INTEGER N) ; %BYTEINTEGERMAP BYTEINTEGER(%INTEGER N) ; %INTEGERFN ADDR(%INTEGERNAME N) ; ; THE CODE IS IDENTICAL FOR ALL THREE!!! ; INT: ENDINT-INT-2/2 MOV (SP)+,R3 ;RETURN ADDRESS MOV (SP)+,R1 ;ADDRESS -> RESULT REGISTER MOV R3,PC ;RETURN ENDINT: ; ; %INTEGERFN ACC ; ACC: ENDACC-ACC-2/2 MOV R0,R1 ;R0 -> RESULT REGISTER RTS PC ;RETURN ENDACC: ; .END