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I. Introduction II. User's guide A. System requirements B. FORTH, calculator style 1. Getting started 2. Compiling definitions 3. Exiting FORTH C. Using the disk 1. FORTH's view of the disk a. Blocks b. Screens 2. Creating and editing new words 3. Compiling source definitions D. Modifying FORTH 1. Saving new FORTH's 2. Patching 3. Assembly source modification E. Glossary extension 1. Assembly listing definitions 2. Deleted words 3. High-level extensions F. FORTH application screens 1. Moving DOS files to FORTH screens 2. Using the screens III. Technical matters A. Modifications to fig-FORTH v1.0 1. Boot parameters 2. Machine code definitions 3. High-level utility definitions 4. Installation dependent code a. Terminal i/o b. Printer i/o c. Disk i/o 5. High-level definitions 6. System tools 7. RAM workspace 8. Memory map III. Future extensions IV. FORTH sources 1 Thi≤ i≤ ß descriptioε oµ modification≤ to¼á anΣ instruction≤ fo≥ usσ of¼ 808╢ fig-FORT╚ v1.0╗ a≤ modifieΣ fo≥ MS-DO╙ by: Joe Smith University of Pennsylvania Dept. of Chemistry 250 S. 33rd St. Philadelphia, PA 19104 I. Introduction Iεá Augus⌠ oµ 1981¼á havinτ aε 8086¼á bu⌠ preciou≤ littlσ t∩ ruεá oεá it¼á ╔á begaε t∩ investigatσá FORT╚á a≤á aεá alternativσ programminτ language«á Thσ fiτ assembl∙ listinτ fo≥ thσ 808╢ wa≤ editeΣá ont∩ disδ durinτ Apri∞ oµ 1982¼á usinτ thσ mnemonic≤á fo≥ Seattlσáá Compute≥á Product≤á 808╢á assembler«áá Oncσá thσá tex⌠ interprete≥ wa≤ running¼ thσ disδ interfacσ wa≤ re-writteε t∩ ruε unde≥ SCP'≤ 86-DOS« Iε augus⌠ oµ 1982¼ sligh⌠ modification≤ werσ madσ t∩ takσ advantagσ oµ feature≤ supporteΣ b∙ MS-DO╙ v1.25. Thσá origina∞ goa∞ wa≤ t∩ instal∞ ß languagσ fo≥ m∙ owε use« Tha⌠á i≤á stil∞ m∙ primar∙á interest«á Fo≥á thi≤á reason¼á thi≤ versioεá oµá thσá languagσá i≤ recommendeΣá fo≥á peoplσá wh∩á arσ familia≥á witΦá thei≥á computer¼á anΣ (somewha⌠á les≤á important⌐ familia≥ witΦ FORTH«á Iµ yo⌡ arσ ne≈ t∩ FORTH¼á yo⌡ wil∞ havσ t∩ diτ fo≥ somσ oµ thσ basiπ information« Whilσ i⌠ i≤ certainl∙ onσ wa∙ t∩ learn¼ i⌠ i≤ slo≈ anΣ sometime≤ frustrating« Iµ yo⌡ arσ ß persoε wh∩ enjoy≤ understandinτ anΣ tinkerinτ witΦ thσ mechanism≤ (reaΣ 'hacker')¼á yo⌡ shoulΣ fee∞ righ⌠ a⌠ home«á Iµ yo⌡ arσ aε experienceΣá FORT╚á user¼á yo⌡ caε tel∞ mσ al∞ thσ thing≤á ╔á diΣ wrong! 2 II. User's guide Thi≤á documentatioεá present≤ specifiπ detail≤ necessar∙á t∩ usσ FORT╚ unde≥ MS-DO╙ (e⌠ al.)«á I⌠ i≤ no⌠ mean⌠ t∩ bσ ß user'≤ guide to FORTH in general. A. System requirements Minimum: 16K + system, no disks Maximum║ 64╦ ½ system¼ ▓ disk≤ ╜ standarΣ configuratioε B. FORTH, calculator style 1. Getting started Afte≥ executinτ FORT╚ b∙ givinτ COMMAN─ thσ namσ oµ thσ .CO═ prograφ wherσ FORT╚ resides¼ ß banne≥ wil∞ appea≥ t∩ le⌠ yo⌡ kno≈ FORT╚á i≤á read∙á t∩ executσá you≥á commands«á Thi≤á i≤á FORTH'≤ executioε state«á A⌠ thi≤ point¼á typσ ß carriagσ return╗ FORT╚ shoulΣá responΣá witΦá 'ok'«á Iµ i⌠ doesn't¼á theεá yo⌡á havσá ß problem« KeyboarΣ entrie≤ arσ handleΣ b∙ thσ FORT╚ worΣ EXPECT¼ whicΦ onl∙ know≤ abou⌠ tw∩ 'specialº keys║á <BACKSPACE╛ anΣ <CR>«á An∙ othe≥ ke∙ i≤ assumeΣ t∩ bσ ß valiΣ character«á N∩ MS-DO╙ editinτ function≤ arσ available«á Thσ exac⌠ ke∙ whicΦ EXPEC╘á recognize≤ a≤á <BACKSPACE╛ i≤ se⌠ iε FORTH'≤ colΣ star⌠ parameter≤ t∩ <CTRL- H╛ ¿ notσ changσ froφ fig¼á wherσ <BACKSPACE╛ ╜ 5╞ he° )« Iµ yo⌡ tr∙á t∩ backspacσ pas⌠ thσ beginninτ oµ thσá line¼á thσá termina∞ shoulΣá bee≡á anΣ leavσ thσ curso≥ a⌠ thσ beginninτ oµ thσá line« Notσ als∩ tha⌠ thσ backspacσ i≤ destructive¼á anothe≥ changσ froφ thσ fig-FORT╚ EXPECT. Othe≥ keyboarΣ function≤ arσ provideΣ b∙á MS-DOS«á <CTRL-S╛ wil∞á pausσ consolσ output╗á <CTRL-P>/<CTRL-N╛ toggle≤á printe≥ echo« <CTRL-C╛ cause≤ executioε oµ thσ FORT╚ worΣ (ABORT)¼ whicΦ execute≤ ABORT¼á haltinτ an∙ i/o¼á resettinτ thσ tex⌠ interprete≥ anΣ printinτ thσ start-u≡ banner«á ABOR╘ clear≤ thσ stacks¼á bu⌠ doesn'⌠á empt∙ thσ disδ buffers«á T∩ tes⌠ thesσ functions¼á typσ VLIS╘á <CR>«á VLIS╘á shoulΣá begiεá printinτá thσá entirσá FORT╚ vocabular∙ a⌠ thσ console«á T∩ pausσ thσ listing¼ typσ <CTRL-S>╗ t∩ abor⌠ thσ listing¼ typσ <CTRL-C>. Notσ tha⌠ (ABORT⌐ ma∙ bσ patcheΣ b∙ FORT╚ t∩ executσ ß user- defined error handler. 2. Compiling definitions Therσá i≤ nothinτ peculia≥ abou⌠ enterinτ definition≤ a⌠ thσ keyboard«á Oncσ yo⌡ typσ ß ':'¼á yo⌡ arσ iε thσ compilinτ state« N∩á 'okºá i≤ printeΣ unti∞ yo⌡ finisΦ you≥ definitioεá witΦá ';'« Definition≤ ma∙ havσ u≡ t∩ 8░ character≤ oε ß line¼á anΣ a≤á man∙ line≤ a≤ needed«á However¼á n∩ editinτ i≤ possiblσ oncσ ß linσ i≤ endeΣ b∙ <CR>«á Iµ yo⌡ makσ ß mistake¼á you≥ definitioε mus⌠á bσ starteΣ over. 3 Try the following definition. : STAR 42 EMIT ;<CR> FORT╚ shoulΣ responΣ 'okº afte≥ yo⌡ typσ thσ <CR>«á No≈ tr∙ you≥ definitioεá b∙ typinτ STAR<CR>«á FORT╚ shoulΣ prin⌠á '*ok'«á Iµ tha⌠ worked¼ tr∙ this: : MILKY-WAY BEGIN STAR SPACE SPACE ?TERMINAL UNTIL ; Remembe≥á yo⌡ won'⌠ ge⌠ aε 'okº unti∞ yo⌡ finisΦá thσá definitioε witΦá thσ semi-colon«á An∙ leadinτ space≤ oε ß linσ arσ ignored« Tes⌠ you≥ definitioε b∙ typinτ MILKY-WAY<CR>« Wheε yo⌡ ge⌠ tireΣ oµ sta≥ gazing¼á sto≡ thσ prograφ b∙ hittinτ an∙ key«á Thσá star≤ should stop, and FORTH should say 'ok'. Iµáá yo⌡á wan⌠á t∩á tr∙á morσá definitions¼áá fee∞á freσá t∩ experiment¼á bu⌠ don'⌠ tr∙ an∙ disδ operations«á A⌠ thi≤á point¼ all you would get is garbage. 3. Exiting FORTH BY┼á i≤ thσ usua∞ fig-FORT╚ worΣ t∩ exi⌠ FORT╚ anΣ returε t∩ the calling program; COMMAND normally, or DEBUG. 4 D. Using the disk 1. FORTH's view of the disk a. Blocks Thσá commoεá FORT╚ mas≤ storagσ devicσ i≤ seeε a≤á ßá simplσ arra∙á oµá blocks¼á referreΣ t∩ b∙ number¼á froφ zer∩ u≡á t∩á thσ physica∞ capacit∙ oµ thσ disk«á Thesσ block≤ arσ accesseΣ iε an∙ orde≥á anΣá completel∙á independen⌠ oµ thσá MS-DO╙á filσá system« Thus¼á FORT╚á canno⌠á acces≤ MS-DO╙ files¼á anΣ FORT╚á disk≤á arσ nonsensσ t∩ MS-DOS«á Fo≥ thi≤ reason¼á yo⌡ wil∞ neeΣ ßá seperatσ disk¼á dedicateΣá t∩á FORT╚á screen≤ ONLY«á Thσ disδá shoulΣá bσ formatteΣá fo≥á single-densit∙á IB═á format«áá Thσá exac⌠áá disδ parameter≤á caε bσ changeΣ t∩ othe≥ formats¼á bu⌠ yo⌡ shoulΣá usσ thσá standarΣ one≤ unti∞ yo⌡ kno≈ wha⌠ yo⌡ arσ doing«á Iµá therσ arσ an∙ file≤ oε thσ disk¼ it'≤ alrigh⌠ becausσ FORT╚ wil∞ ignorσ them« b. Screens Internally¼á FORT╚á see≤á thσá disδ a≤á block-sizeΣá pieces╗ however¼á thσ use≥ i≤ presenteΣ witΦ ßá fixed¼á 1024-byte¼á chunδ referreΣá t∩ a≤ ß screen«á Notσ tha⌠ ß screeε may¼á o≥ ma∙á not¼ corresponΣá t∩ onσ block«á ┴ FORT╚ screeε appear≤ a≤ 1╢ line≤ oµ 6┤á characters«á Thi≤á i≤ ONL┘ fo≥ appearancσ íá Therσá arσá n∩ physica∞á <CR>/<LF╛á character≤á betweeεá lines¼áá anΣá thσá 63rΣ characte≥á iεá an∙á linσá i≤á logicall∙á adjacen⌠á t∩á thσá firs⌠ characte≥ iε thσ followinτ line«á Thσ firs⌠ linσ oµ tex⌠ screen≤ i≤ usuall∙ reserveΣ fo≥ ß shor⌠ descriptioε oµ thσ contents. Usinτá 128-bytσá blocks¼á aε 8ó disδ iε thσ standarΣá forma⌠ hold≤ 187▓ block≤ ¿ 0-187▒ )¼á o≥ 23┤ screen≤ ¿ 0-23│á )«á Blocδ 1872 is the first block on drive 1. T∩á tes⌠ FORTH'≤ disδ interface¼á tr∙ thσá following«á Star⌠ FORT╚ and¼á afte≥ yo⌡ ge⌠ thσ 'ok'¼ replacσ you≥ systeφ disδ witΦ ß scratcΦ disδ a≤ describeΣ above« Bσ prepareΣ t∩ LOS┼ AN┘ FILE╙ oεá thi≤ diskíá Checδ thσ curren⌠ screeε b∙ typinτ 'SC╥ ?º «á I⌠ shoulΣ bσ ┤ ¿ whicΦ i≤ thσ initia∞ valuσ fo≥ thσ variablσ SC╥á )« Iµá i⌠ isn't¼á typσ COLD¼á anΣ repea⌠ thσ abovσá procedure«á Thσ curren⌠ screeε shoulΣ no≈ bσ 4« Typσ EDITO╥ t∩ selec⌠ thσ edito≥ vocabulary¼á theεá ente≥ 'WIPEº t∩ fil∞ thi≤ screeε witΦá blanks« Don'⌠ bσ alarmeΣ iµ therσ i≤ n∩ disδ activit∙ a⌠ thi≤ point« No≈ typσ 'Lº t∩ vie≈ thσ screeε - i⌠ shoulΣ bσ al∞ blanks«á No≈ typσ 'FLUSH'«á No≈á therσá shoulΣ bσ somσ disδá activity¼á anΣá FORT╚ shoulΣ returε 'ok'« Iµ therσ seem≤ t∩ bσ somσ problem¼ d∩ ß COL─ start¼á anΣ tr∙ again«á Iµ thσ probleφ persists¼á makσ surσá thσ scratcΦá disδ i≤ properl∙ formatted¼á anΣ tr∙ again«á Hopefully¼ therσ won'⌠ bσ an∙ hangups¼á anΣ you'l∞ ge⌠ thσ 'ok'«á No≈á typσ 'Lºá again«á FORT╚á shoulΣ g∩ bacδ t∩ thσ disk¼á theεá lis⌠á thσ blanδá screen«á 5 Ente≥ somσ tex⌠ int∩ linσ zer∩ oµ thσ screeε b∙ typinτ '░ Tº followeΣá b∙ '╨ ¿ thi≤ i≤ screeε 4¼á linσ ░ )'«á Lis⌠ thσ screeε agaiε t∩ makσ surσ thσ tex⌠ i≤ properl∙ placed¼á anΣ usσ FLUS╚ t∩ senΣ i⌠ t∩ thσ disk« Wheε yo⌡ typσ 'Lº again¼ thσ tex⌠ shoulΣ bσ jus⌠ a≤ yo⌡ lef⌠ it. 2. Creating and editing new words Therσá arσá tw∩ line-orienteΣ editor≤ includeΣ iε thσá FORT╚ screens« Onσ i≤ thσ edito≥ a≤ describeΣ iε "Startinτ FORTH"╗ thσ othe≥áá i≤á thσá fig-FORT╚á portablσá edito≥á describeΣá iεáá thσ Installatioεá Manual«á Thσá editor≤ ma∙ bσ useΣ t∩ placσá sourcσ tex⌠á oε disk¼á wherσ i⌠ caε bσ modifieΣ withou⌠á re-writinτá thσ wholσá definition«á Thσ edito≥ describeΣ iε "Startinτ FORTHó ha≤ beeε compileΣ anΣ includeΣ iε thσ .CO═ file. Tr∙á editinτá thσ definition≤ abovσ fo≥ STA╥á anΣá MILKY-WA┘ onto a screen on your scratch disk. 3. Compiling source screens Wheεá yo⌡ havσ finisheΣ enterinτ thσ definitions¼á usσ FLUS╚ t∩ makσ surσ thσ disδ ha≤ thσ lates⌠ versioε oµ thσ screen¼á theε typσ '┤ LOAD'« Iµ FORT╚ say≤ 'ok'¼ tes⌠ you≥ ne≈ version≤ oµ thσ definition≤á t∩ makσ surσ the∙ werσ compileΣ correctly«á Iµá yo⌡ ge⌠á aε erro≥ whilσ loading¼á usσ WHER┼ t∩ seσ thσ linσ wherσ thσ problem is. Iµ everythinτ look≤ 'okº u≡ t∩ thi≤ point¼á theε yo⌡ caε usσ DEBU╟, a≤ describeΣ below anΣ iε thσ termina∞ sessioε listing¼ t∩ movσá thσ MS-DO╙ filσ oµ FORT╚ screen≤ ove≥ t∩ you≥ scratcΦá disδ where FORTH can use them. 6 E« Modifyinτ FORTH 1. Saving new FORTHs Onσ oµ thσ nicσ thing≤ abou⌠ FORT╚ i≤ thσ abilit∙ t∩á extenΣ thσ language«á Iµ yo⌡ definσ ß worΣ whicΦ yo⌡ wan⌠ t∩ usσ often¼ withou⌠ re-compilinτ i⌠ ever∙ time¼ yo⌡ caε savσ thσ change≤ iε ß ne≈ .CO═ file«á Thσ proces≤ involve≤ usinτ DEBU╟ t∩ loaΣ FORTH'≤ ì FORT╚ itselµ )¼ executinτ thσ FORT╚ word≤ NE╫ ¿ whicΦ update≤ al∞ ì thσ COL─ star⌠ parameter≤ ⌐ anΣ SIZE┐á ¿ whicΦ tell≤ yo⌡ ho≈á biτ ì thσá ne≈ dictionar∙ i≤ )¼á theε exitinτ FORT╚ anΣ usinτ DEBU╟á t∩ ì writσá thσá ne≈á .CO═ file«á Fo≥ ßá detaileΣá example¼á seσá thσ ì termina∞ sessioε listing. FORTH'≤áá .CO═á filσá a≤á distributeΣá wa≤á constructeΣáá b∙ assemblinτ thσ source¼á theε LOADinτ additiona∞ word≤ ¿ includinτ thσá edito≥ )¼á anΣ savinτ thσ resultinτ dictionar∙ usinτá DEBUG« ì Thσ FORT╚ screen≤ loadeΣ t∩ producσ FORTH.CO═ caε bσ founΣ iε thσ ì termina∞ sessioε listing. 2. Patching Mostá oµ thσ parameter≤ whicΦ affec⌠ thσ operatioε oµá FORT╚ arσ placeΣ iε thσ boot-u≡ paramete≥ areß a⌠ thσ lo≈ enΣ oµ FORTH« Thesσ ma∙ bσ freel∙ modifieΣ usinτ DEBUG¼á o≥ froφ withiεá FORTH« Oεá executioεá oµá COLD¼á thσ change≤ wil∞ bσá incorporateΣá int∩ FORTH« Patche≤ sucΦ a≤ thi≤ caε bσ madσ permanen⌠ usinτ DEBUG. 2. Assembly source modification Change≤á no⌠ possiblσ througΦ thσ othe≥ tw∩ method≤á caεá bσ incorporateΣá int∩á thσ assembl∙ source«á Yo⌡ caε stud∙ thσá fiτ listinτ fo≥ detail≤ oε thσ inne≥ working≤ oµ thσ interpreter;á o≥ my listing for details specific to MS-DOS. Notσá thσá alignmen⌠ requirements«á Thσ ALIG╬ pseudo-o≡á i≤ ì requireΣá wheεá thσá namσá lengtΦ i≤á even¼á anΣá als∩á wheεá thσ ì alignmen⌠á ma∙á havσ beeε los⌠ iε thσá previou≤á word«á Thi≤á i≤ ì s∩ tha⌠ yo⌡ caε calculatσ thσ linδ fielΣ fo≥ thσ followinτ word. Bσá awarσ oµ tw∩ problem≤ here║á first¼á i⌠ i≤ ver∙ eas∙á t∩ losσáá tracδáá oµá thσá change≤á yo⌡á make¼áá s∩á documen⌠áá EAC╚ modification«á Second¼á morσ change≤ makσ you≥ versioε oµá FORT╚ morσ uniquσ ¿ o≥ maybσ jus⌠ strangσ )¼á anΣ an∙ definition≤ usinτ tha⌠á uniquσ featurσ les≤ portable«á WeigΦ thesσ factor≤á beforσ makinτ change≤ t∩ thσ source«á Don'⌠ adΣ bell≤ anΣ whistle≤ jus⌠ to be different. 7 F. Glossary extension Thσá followinτá i≤á aε extensioε oµ thσá fig-FORT╚á glossar∙ included in the fig Installation manual. 1. Assembly listing additions Thσá followinτá word≤ werσ addeΣ t∩á thσá assembl∙á listing« They are all CODE level words. (2ARR) n1 n2 PFA -- addr Tw∩á dimensiona∞ arra∙ primitivσ useΣ b∙ 2ARRAY«á Thσ addres≤ oµ thσ arra∙ elemen⌠ a⌠ ro≈ n1¼á columε n▓ oµ aε arra∙ beginninτá a⌠ PFA+┤á i≤á lef⌠ oε thσ stack«á I⌠ i≤ assumeΣ tha⌠ thσ rowsizσá ¿ i.e.¼á ú column≤ ⌐ i≤ storeΣ a⌠ PFA« Thσ content≤ oµ PFA+▓ woulΣ normall∙á holΣá thσá numbe≥á oµ rows¼á bu⌠ i≤á no⌠á useΣá iεá thσ calculation. (2CARR) n1 n2 PFA -- addr Tw∩á dimensiona∞á bytσá arra∙ primitivσá useΣá b∙á STRINGS«á Thσ addres≤á oµá thσ arra∙ elemen⌠ a⌠ ro≈ n1¼á columε n▓ oµ aεá arra∙ beginninτ a⌠ PFA+┤ i≤ lef⌠ oε thσ stack«á I⌠ i≤ assumeΣ tha⌠ thσ rowsizσá i≤ storeΣ a⌠ PFA«á Thσ content≤ oµ PFA+▓ coulΣ holΣ thσ numbe≥á oµ row≤ o≥ thσ curren⌠ lengtΦ oµ thσ string╗á i⌠á i≤á no⌠ useΣ iε thσ calculation. (ARRAY) n PFA -- addr Intege≥á arra∙ primitivσ useΣ b∙ ARRAY«á Thσ addres≤ oµ thσá ntΦ elemen⌠ iε thσ arra∙ beginninτ a⌠ PFA+▓ i≤ calculateΣ anΣ lef⌠ oε the stack. The length of the array is stored at PFA. (CARR) n PFA -- addr Bytσá arra∙á primitivσ useΣ b∙ CARRAY«á Thσ addres≤ oµá thσá ntΦ characte≥ iε thσ arra∙ beginninτ a⌠ PFA+▓ i≤ calculateΣ anΣá lef⌠ oε thσ stack«á Thσ lengtΦ oµ thσ array¼ o≥ curren⌠ lengtΦ oµ thσ string may be stored at PFA. (XOF) n1 n2 -- n1 ( no match, n1<>n2 ) n1 n2 -- ( match, n1=n2 ) Contro∞á structurσ primitivσ compileΣ b∙ OF«á Iµ thσ casσá beinτ scanneΣá fo≥ (n1⌐ matche≤ thσ curren⌠ casσ (n2)¼á thσ taτá n▒á i≤ dropped¼á anΣ thσ FORT╚ word≤ followinτ thσ brancΦ compileΣ b∙ O╞ arσ executed«á Iµ thi≤ i≤ no⌠ thσ casσ selected¼ thσ taτ i≤ lef⌠ oε thσ stack¼ anΣ scanninτ continue≤ witΦ thσ nex⌠ case. 1- n -- n-1 2- n -- n-2 Decrement operators. 8 :! n seg offset -- :@ seg offset -- n :C! n seg offset -- :C@ seg offset -- n Fa≥ fetch/storσ operators«á Thesσ arσ simila≥ t∩ thσ usua∞ FORT╚ fetch/storσ words¼á excep⌠ the∙ usσ ß double-worΣ address«á Notσ that the absolute location accessed is: seg*16 + offset. BLOCK-READ -- BLOCK-WRITE -- Primitivσá routine≤ responsiblσ fo≥ disδ access«á Thesσ routine≤ usσá thσá FORT╚ variable≤ DRIVE¼á USE¼á SEC/BLK¼á anΣá RECOR─á t∩ transfe≥á thσá appropriatσá numbe≥ oµ disδá record≤á to/froφá thσ buffe≥á specifieΣá b∙á USE«á Thσ FORT╚á variablσá DISK-ERRO╥á i≤ set/rese⌠á t∩á signa∞á aεá error«á DISK-ERRO╥á i≤á zer∩á iµá thσ operatioεá wa≤ successful╗á non-zer∩ iµ not«á Thσ erro≥ codσá i≤ tha⌠ returneΣ b∙ thσ MS-DO╙ read/writσ interrupt≤ ¿ 25╚ ª 26╚á )¼ excep⌠ tha⌠ writσ error≤ are negative. DATE! mon day yr -- DATE@ -- yr day mon Datσ fetch/storσ operators«á Iµ an∙ oµ thσ parameter≤ arσ ou⌠ oµ range, no changes are made. MYSEG -- seg Thi≤á worΣá return≤ thσ valuσ oµ FORTH'≤ curren⌠á segment«á Thi≤ allow≤á thσá thσ fa≥ fetch/storσ operator≤á t∩á acces≤á location≤ inside FORTH in the usual way. PRINTER -- addr ┴á variablσ whicΦ cause≤ consolσ i/∩ t∩ bσ echoeΣ t∩ thσ printer« Iµ PRINTE╥ i≤ non-zero¼á thσ printe≥ i≤ 'on'«á Notσ tha⌠ thi≤ i≤ independen⌠ oµ thσ <CTRL-P>/<CTRL-N╛ ech∩ ! RECORD -- addr ┴á variablσ whicΦ contain≤ thσ numbe≥ oµ thσ las⌠ logica∞á recorΣ accessed«á RECOR─á i≤ se⌠ b∙ T&SCAL├ anΣ useΣ b∙ BLOCK-REA─á anΣ BLOCK-WRITE. TIME! [sec csec] [hr min] -- TIME@ -- [sec csec] [hr min] Timσá store/fetcΦ operators«á Thesσ routine≤ set/ge⌠ thσá systeφ time« Iµ an∙ oµ thσ parameter≤ arσ invalid¼ n∩ change≤ arσ made« Al∞ oµ thσ value≤ arσ bytes¼á bu⌠ arσ packeΣ int∩ ▓ words╗á i.e.¼ thσá lo≈ bytσ oµ thσ to≡ stacδ iteφ hold≤ thσ minutes¼á thσá higΦ byte holds the hours, and so on. 9 2. Deleted words Thσá followinτá word≤ appearinτ iε thσ fiτ assembl∙á listinτ were not used, and therefore deleted. SEC TRACK SET-IO SET-DRIVE SECRD SECWT 3. High-level extensions. Thσá followinτá word≤ werσ addeΣ b∙ compilinτ FORT╚á screen≤ anΣá savinτá thσ ne≈ versioε oµ FORT╚á usinτá DEBUG«á Thσá FORT╚ sourcσ fo≥ al∞ oµ thesσ word≤ i≤ includeΣ iε thσ screeε file. ARRAY 2ARRAY STRING STRINGS ▒ anΣ ▓ dimensiona∞ arra∙ defininτ words« Seσ thσ sourcσ screen≤ for more comments. CASE OF ENDOF ENDCASE Thesσá word≤á adΣá ß casσ construc⌠ t∩á FORTH«á The∙á havσá beeε documenteΣá iεá severa∞ differen⌠ places«á Seσ screeε 2▓ fo≥á aε example. DUMP addr -- addr2 Thi≤á worΣá display≤ thσ content≤ oµ locatioεá add≥á t∩á addr2-1╗ addr▓á i≤á lef⌠ oε thσ stacδ s∩ tha⌠ DUM╨ caε bσ entereΣá withou⌠ keepinτ tracδ oµ thσ address«á Thσ dum≡ i≤ iε thσ curren⌠ numbe≥ base«á ┴á variablσ SEGMEN╘ i≤ useΣ a≤ thσ base¼á anΣ add≥ i≤á aε offset in that segment. SEGMENT is initialized to MYSEG. NEW -- NE╫ update≤ thσ start-u≡ parameter≤ t∩ reflec⌠ thσ curren⌠á statσ oµá FORTH«á Thi≤ allow≤ compileΣ definition≤ t∩ bσ retaineΣ wheε COL─ i≤ executed«á Notσ tha⌠ oncσ NE╫ i≤ executed¼á iµ thσ addeΣ word≤á arσá deleteΣ b∙ FORGET¼á thσ start-u≡ parameter≤á wil∞á bσ wrong, and NEW must be done again before a cold start. SIZE? -- Show≤á thσá curren⌠ sizσ oµ thσ FORT╚ dictionary¼á anΣá thσá freσ spacσ remaining«á Thi≤ i≤ primaril∙ usefu∞ fo≥ tellinτ DEBU╟ ho≈ biτá ß filσ t∩ creatσ wheε savinτ ß ne≈ versioεá oµá FORTH«á NE╫ must be run before saving a different version. 10 G. FORTH application screens 1. Moving DOS files to FORTH screens Occasionall∙á i⌠ ma∙ bσ usefu∞ t∩ havσ FORT╚ screen≤á residσ iε ß DO╙ file« DEBU╟ ma∙ bσ employeΣ t∩ transfe≥ screen≤ betweeε thσ tw∩ environments«á Bσ careful¼ back-u≡ botΦ disk≤ BEFOR┼ yo⌡ makσ ß mistake« Seσ thσ termina∞ sessioε listing≤ fo≥ ß detaileΣ example. 2. Using the screens Sincσá mos⌠á oµ thσ screen≤ arσ simplσ utilties¼á thei≥á usσ shoulΣ bσ self-evident«á Hopefully¼á iε thσ future¼ morσ comple° applications can be distributed. LIFE Thσá LIF┼á prograφá provideΣ i≤ nicσ t∩ watch¼á bu⌠ i≤á no⌠á ver∙ clearl∙á written«á Yo⌡ wil∞ havσ t∩ writσ you≥ owεá routine≤á t∩ positioε thσ curso≥ oε you≥ terminal« Thσ word≤ oε screeε 3▒ ma∙ servσá a≤ ß model«á Afte≥ loadinτ thσ firs⌠ screeε ¿ 3╡ LOA─á )¼ FORT╚á wil∞á inforφá yo⌡ ho≈ t∩ star⌠ thσ game«á T∩ se⌠á u≡á thσ board¼á usσá <SPACE╛ » <BACKSPACE╛ t∩ movσ thσ curso≥ righ⌠á anΣ left¼á anΣ <LINEFEED╛ t∩ movσ down¼á o≥ <CR╛ t∩ movσ dowε anΣá t∩ the beginning of the line. <ESC> starts the activity. 11 III. Technical matters A. Modifications to fig-FORTH v1.0 Thi≤á sectioε describe≤ specifiπ change≤ t∩ thσ fiτá listinτ a≤á outlineΣá iεá thσ Installatioε Manual«á Thσá heading≤á belo≈ corresponΣ t∩ thosσ iε thσ manual╗á iµ n∩ change≤ arσá noted¼á n∩ change≤ havσ beeε madσ t∩ tha⌠ par⌠ oµ thσ model. 1. Boot parameters 14 +ORIGIN ( BSIN ) Changed to 08 ( ASCII CTRL-H ) 2. Machine code definitions (FIND⌐ ChangeΣ t∩ accomodatσ word-aligneΣ LFA's« Seσ CREAT┼ below. 3. High-level utility definitions 1+ 2+ Changed to CODE level definitions. TRAVERSE Modified to handle word-aligned LFA's PFA Modified to handle word-aligned PFA's EXPECT Backspace made destructive ID. Modified to reset MSB of last character CREAT┼á ModifieΣá t∩ compilσ dictionar∙ entrie≤ witΦá word- aligneΣá LFA«á Iµá D╨ i≤ odΣ afte≥ compilinτá thσá name¼á D╨á i≤ incremented¼á s∩á tha⌠á thσ res⌠ oµ thσ definitioε fall≤ a⌠á eveε adresses«á Iµá bytσá value≤á arσ compileΣá int∩á thσá definitioε subsequently¼á thσ alignmen⌠ ma∙ bσ lost«á Notσ tha⌠ thσá lengtΦ bytσá a⌠á NF┴ stil∞ give≤ thσ exac⌠ lengtΦ oµ thσ name¼á bu⌠á no⌠ necessaril∙ thσ displacemen⌠ t∩ thσ LFA. QUIT Prints lower case 'ok' ABORT Changed to print the user version as well COLD Sets SCR to 4 4. Installation dependent code a. Terminal i/o (KEY) uses MS-DOS function 8 (EMIT) uses MS-DOS function 2 (?TERMINAL) uses MS-DOS function 11 (CR) uses MS-DOS function 2 b. Printer i/o EPRINT Changed to PRINTER 12 c. Disk i/o Al∞á disδá parameter≤á werσ moveΣ t∩ thσá beginninτá oµá thσ listing¼á anΣ al∞ LITERA╠ parameter≤ iε definition≤ werσá changeΣ t∩ usσ thσ EQ╒ symbols¼á o≥ FORT╚ variable≤ ¿ +BUF¼á R/╫ )« Al∞ disδá i/∩á i≤ donσ througΦ thσ blocδ read/writσá interrupt≤á 25H¼ 26H«á Thσá variable≤á DISK¼á RECORD¼á SEC/BL╦ anΣ US┼ servσá t∩ specif∙ thσ disδ record anΣ transfe≥ address. T&SCAL├ set≤ DIS╦ anΣ RECOR─ froφ thσ blocδ numbe≥ supplieΣ b∙ R/W. R/╫ call≤ T&SCALC¼ theε BLOCK-REA─ o≥ BLOCK-WRITE« Iµ DISK- ERRO╥ i≤ non-zero¼á messagσ #╕ i≤ issueΣ anΣ thσ buffe≥ i≤ markeΣ a≤á unused«á DISK-ERRO╥ caε bσ examineΣ b∙ thσ use≥ t∩ finΣá thσ exac⌠á causσ oµ thσ error«á Thσ erro≥ code≤ arσ a≤ specifieΣá iε thσá MS-DO╙ documentation¼á excep⌠ writσ error≤ arσá returneΣá a≤ negativσá number≤ ¿ e.g«á DISK-ERRO╥ ╜ -▓ fo≥ no⌠ read∙ erro≥á oε writσ operatioε ). 5. High-level definitions 6. System tools 7. Ram workspace 8. Memory map Thσá memor∙ ma≡ wa≤ expandeΣ t∩ usσ al∞ 64╦ ¿ LIMI╘ ╜á ░á )¼ and 16 block-buffers. 9. Other COL─á set≤á thσ <CTRL-C╛ interrup⌠ vecto≥ ¿ MS-DO╙á functioε 25Φ ⌐ t∩ thσ addres≤ oµ ß codσ fragmen⌠ whicΦ vector≤ thσá inter- prete≥ t∩ (ABORT). BYE causes execution of interrupt 20h. 13 H. Future extensions Therσá arσ ß numbe≥ oµ thing≤ ╔ woulΣ likσ t∩ adΣ t∩á FORTH╗ al∞á involvσ ß certaiε amoun⌠ oµ work¼á anΣ somσ arσ no⌠á a⌠á al∞ trivial«á Iµá yo⌡á arσ interesteΣ iε makinτ somσ suggestion≤á o≥ contributinτá an∙ changes¼á ╔ woulΣ certainl∙ enjo∙á talkinτá anΣ trading. A list of these extensions would include: Immediate future: High-level character string operators High-level floating point Screen editor(s) Assembler CommanΣ linσ argument≤ ¿ thi≤ i≤ ßá ver∙ simple possibility, I just haven't found a good use for it ) Nea≥á future║á Rea∞ MS-DO╙ filσ interfacσ ¿ no⌠á jus⌠ random access ) I/O redirection via execution vectors CODE level character string functions ??? future: Cross/target compiler COD┼ leve∞ floating-poin⌠ » 808╖ support Multi-segmented Multi-tasking Tree structured vocabularies/file system High-level interrupt handling 14 IV« FORT╚ sources Thσáá followinτáá arσá source≤á oµáá informatioεáá regardinτ implementatioε anΣ usσ oµ FORTH. Startinτ FORTH« Le∩ Brodie¼ FORTH¼ Inc« Prentice-Hal∞ 1981 Excellen⌠ introductor∙ material. Byte¼ vol.╡ no.8¼ Augus⌠ 1980 Languagσá issuσá devoteΣ t∩ FORTH«á GooΣ discussioεá oµá defininτ word≤ anΣ FORT╚ internals. Dr« Dobb≤ Journal¼ vol.╢ no.9¼ Septembe≥ 1980 Dr« Dobb≤ Journal¼ vol.╖ no.9¼ Septembe≥ 1981 Issue≤ devoteΣ t∩ FORT╚ topics. FORT╚ Interes⌠ Group P.O« Bo° 1105 Saε Carlos¼ C┴ 94070 Publiπ domaiε listings¼ bi-monthl∙ newlette≥ FORT╚ Dimensions. 15 This disk copy was originally provided by "The Public Library", the software library of the Houston Area League of PC Users. Programs are available from the Public Library at $2 per disk on user-provided disks. To get a listing of the disks in the Public Library, send a self-addressed, stamped envelope to Nelson Ford, P.O.Box 61565, Houston, TX 77208.