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altodEFS.mESA 24-0CT-77 21;15;31 Page 1


-- AltoDefs.Mesa Edited by Satterthwaite on February 9, 1977 1:43 PM
AltoDefs: DEFINITIONS
BEGIN
wordlength: INTEGER = 16; Alto word length (bits)
maxword: CARDINAL = 1777778; N.B. negative as 16 bit number
maxinteger: INTEGER 077777B; -- maximum positive number
charlength: INTEGER 8; Alto character size (bits)
maxcharcode: INTEGER = 3778;
BYTE: TYPE = [0 .. maxcharcode];
BytesPerWord, CharsPerWord: INTEGER = wordlength/charlength;
LogBytesPerWord, LogCharsPerWord: INTEGER = 1;
Page~ize: INTEGER" 256; -- Alto page size (words)
LogPageSize: INTEGER = 8;
BytesPerPage, CharsPerPage: INTEGER = PageSize*CharsPerWord;
LogBytesPerPage, LogCharsPerPage: INTEGER" LogPageSize+LogCharsPerWord;
VMLimit: CARDINAL = 177777B; maximum Alto VM address
Address: TYPE" [0 .. VMLimit];
MaxVMPage: INTEGER" 255: maximum Alto VM page number
MaxFilePage: CARDINAL" 077777B;
PageNumber: TYPE" [0 .. MaxFilePage];
PageCount: TYPE" [0 .. MaxVMPage+l];
END.