F.I.G. Forth

* FIG FORTH FOR SERIES-16 MACHINES PAGE 4

0134 ****************************************************************** 0135 * 0136 * VARIATIONS FROM F.I.G. MODEL 0137 * 0138 ****************************************************************** 0139 * 0140 * THESE DIFFERENCES WERE INHERITED FROM THE PDP-11 0141 * IMPLEMENTATION: 0142 * 0143 * 0144 * 'FIRST' AND 'LIMIT' HAVE BEEN MADE USER VARIABLES, NOT 0145 * CONSTANTS. THEREFORE WHEN THEY ARE USED, 'FIRST @' AND 0146 * 'LIMIT @' ARE REQUIRED. 0147 * 0148 * ';CODE' AND 'FORTH' ARE NOT PURE CODE, SO THEY WERE MOVED TO 0149 * THE END OF THE DICTIONARY. THIS IS SO THE BULK OF THE 0150 * DICTIONARY COULD BE PUT IN PROM OR USED RE-ENTRANTLY. 0151 * 0152 * THE MACHINE-INDEPENDENT I/O SECTION WAS MOVED TO NEAR THE END 0153 * OF THE DICTIONARY, BECAUSE IT IS NOT ALWAYS PURE CODE, AND ALSO 0154 * TO ALLOW THE I/O TO BE REDEFINED WITHOUT REASSEMBLY. 0155 * 0156 * THIS SYSTEM MUST TEST FOR FIRST-TIME-THROUGH TERMINAL AND DISK 0157 * I/O, TO AVOID ERRONEOUS ATTEMPT TO OPEN FILES TWICE AT LATER 0158 * COLD STARTS. IT CLEARS DISK BUFFERS AT COLD START. 0159 * 0160 * ***** ***** ***** ***** ***** ***** ***** ***** ***** 0161 * 0162 * THESE DIFFERENCES WERE INHERITED FROM THE NOVA 0163 * IMPLEMENTATION: 0164 * 0165 * 0166 * ALL MEMORY REFERENCES ARE CELL ADDRESSING EXCEPT: 0167 * ENCOSE, CMOVE, C@, C!, -TRAILING, HOLD, (NUMBER), NUMBER 0168 * 0169 * TRAVERSE IS NOT NEEDED FOR NFA PROCESSING 0170 * 0171 * BRANCH, 0BRANCH, (LOOP), AND (+LOOP) USE THE ACTUAL 0172 * DESTINATION ADDRESS, NOT THE OFFSET FROM THE CURRENT 0173 * ADDRESS 0174 * 0175 * ?TERMINAL RETURNS TRUE AFTER ANY KEYSTROKE 0176 * 0177 * ADDED WORDS ARE: BYTE, CELL, U< 0178 * 0179 * ***** ***** ***** ***** ***** ***** ***** ***** ***** 0180 * 0181 * IN ADDITION THE FOLLOWING DIFFERENCES ARE PECULIAR TO THIS 0182 * SERIES-16 IMPLEMENTATION: 0183 *