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Finally, the screen driver may create user defined characters by the following combination which specifies the rows on a 6x8 matrix:
1, 138, '=', charcode, r0, r1, r2, r3, r4, r5, r6, r7
Note that the count of 10 is specified in numeric form with the top bit set (138) as it will not fit in a single digit. If you use a smaller count, the unspecified rows will be set to 0. This can be useful since most system characters have a blank bottom row. The number 'charcode' is the character code of the defined character and must be between 64 ('@') and 127 (DEL) inclusive providing 64 user characters on an expanded machine. On an unexpanded machine (ie. without 128K or more in slot 1) only 16 characters can be defined without encroaching on the memory used for the PipeDream map. Characters above the limit of 16, will have their definitions overwritten by map information when PipeDream is used. If the map width is 64 pixels or less then the full 64 user characters can be used.
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