Difference between revisions of "83Plus:Hooks:9B9C"

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'''Note:''' Do not take the information on this template page as actual documentation!
 
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The Hooks are named by their hook pointer block address (the four bytes consisting of page, address, and an extra byte), in hexadecimal. An example is [[83Plus:Hooks:9B84]].
 
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----
 
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== Synopsis ==
 
== Synopsis ==
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'''Name:''' ImAHook
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'''Name:''' Font Hook
  
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'''Hook Pointer Block Address:''' [[83Plus:RAM:8562|8562]]
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'''Hook Pointer Block Address:''' [[83Plus:RAM:9B9C|9B9C]]
  
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'''Hook Enable BCALL:''' [[83Plus:BCALLs:1234|1234]]
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'''Hook Enable BCALL:''' [[83Plus:BCALLs:4FE4|4FE4]]
  
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'''Hook Disable BCALL:''' [[83Plus:BCALLs:5678|5678]]
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'''Hook Disable BCALL:''' [[83Plus:BCALLs:4FE7|4FE7]]
  
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'''Hook Call BCALL:''' [[83Plus:BCALLs:9012|9012]]
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'''Hook Call BCALL:''' [[83Plus:BCALLs:4003|4003]]
  
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'''Hook Active Flag:''' 6, (iy + 23h)
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'''Hook Active Flag:''' [[83Plus:BCALLs:35#Bit_5|5, (iy + 35h)]]
  
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This hook allows you to change the values that [[83Plus:BCALLs:4972|GetKey]] returns.
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This hook allows you to change the font bitmaps; for example, it is used for [http://www.detachedsolutions.com/omnicalc/ Omnicalc]'s custom fonts.
  
 
== Using the Hook ==
 
== Using the Hook ==
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These different values, passed in a, determines what the hook should do.
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* A = 0 for small font, 1 for large font
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* 1: The calculator just turned on. There seem to be no other values passed to the hook.
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* B = character
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* 2: The calculator is computing 1+1.
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* NZ to use the default bitmaps (or rather, the bitmaps provided by the [[83Plus:Hooks:9BCC|localize hook]])
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** b: 1
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* Otherwise, set HL pointing to the font data, which must be in RAM:
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** c: 1
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** In small font:
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** Change b and/or c to affect the output of the problem (which will still look like 1+1 to the user).
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*** (HL) = width of character
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* 3: Preparing to turn off due to 2nd+OFF.
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*** (HL+1) = first (accent) row, right aligned (with the last pixel usually clear)
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** Zero flag: Clear to abort the power off.
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*** (HL+2) = second row
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*** ...
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*** (HL+6) = sixth row
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*** (HL+7) = seventh row (only displayed with bit [[83Plus:Flags:5#Bit_1|textEraseBelow, (iy+textFlags)]] set)
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** In large font:
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*** (HL) = first row, right aligned
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*** ...
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*** (HL+6) = seventh row
  
 
== Comments ==
 
== Comments ==
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This hook doesn't exist. This is a demonstration only.
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This hook is one of the four "official" hooks defined in ti83plus.inc.
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== Example ==
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The following code displays the letter A in boldface:
  
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== Credits and Contributions ==
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<nowiki>FontHook:
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* '''/dev/hda1:''' My favorite hard drive partition.
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        .db 83h            ; Required for all hooks
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        or a                ; is it small or large font?
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        jr z,SmallFont
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        ld a,b              ; what character is to be displayed?
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        cp 'A'
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        ret nz
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        ld hl,BigA          ; get our replacement bitmap
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        ld de,lFont_record
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        ld bc,7            ; copy it into RAM
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        ldir
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        ld hl,lFont_record
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        cp a
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        ret
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SmallFont:
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        ld a,b              ; what character is to be displayed?
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        cp 'A'
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        ret nz
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        ld hl,SmallA        ; get our replacement bitmap
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        ld de,sFont_record
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        ld bc,8            ; copy it into RAM
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        ldir
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        ld hl,sFont_record
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        cp a
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        ret
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BigA:
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        .db 00001110b
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        .db 00010011b
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        .db 00010011b
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        .db 00011111b
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        .db 00010011b
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        .db 00010011b
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        .db 00010011b
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SmallA:
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        .db 5
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        .db 00000000b
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        .db 00001100b
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        .db 00010110b
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        .db 00011110b
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        .db 00010110b
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        .db 00010110b
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        .db 00000000b</nowiki>

Revision as of 22:40, 27 March 2005

Synopsis

Name: Font Hook

Hook Pointer Block Address: 9B9C

Hook Enable BCALL: 4FE4

Hook Disable BCALL: 4FE7

Hook Call BCALL: 4003

Hook Active Flag: 5, (iy + 35h)

This hook allows you to change the font bitmaps; for example, it is used for Omnicalc's custom fonts.

Using the Hook

  • A = 0 for small font, 1 for large font
  • B = character
  • NZ to use the default bitmaps (or rather, the bitmaps provided by the localize hook)
  • Otherwise, set HL pointing to the font data, which must be in RAM:
    • In small font:
      • (HL) = width of character
      • (HL+1) = first (accent) row, right aligned (with the last pixel usually clear)
      • (HL+2) = second row
      • ...
      • (HL+6) = sixth row
      • (HL+7) = seventh row (only displayed with bit textEraseBelow, (iy+textFlags) set)
    • In large font:
      • (HL) = first row, right aligned
      • ...
      • (HL+6) = seventh row

Comments

This hook is one of the four "official" hooks defined in ti83plus.inc.

Example

The following code displays the letter A in boldface: 

FontHook:
        .db 83h             ; Required for all hooks
        or a                ; is it small or large font?
        jr z,SmallFont
        ld a,b              ; what character is to be displayed?
        cp 'A'
        ret nz
        ld hl,BigA          ; get our replacement bitmap
        ld de,lFont_record
        ld bc,7             ; copy it into RAM
        ldir
        ld hl,lFont_record
        cp a
        ret
SmallFont:
        ld a,b              ; what character is to be displayed?
        cp 'A'
        ret nz
        ld hl,SmallA        ; get our replacement bitmap
        ld de,sFont_record
        ld bc,8             ; copy it into RAM
        ldir
        ld hl,sFont_record
        cp a
        ret
BigA:
        .db 00001110b
        .db 00010011b
        .db 00010011b
        .db 00011111b
        .db 00010011b
        .db 00010011b
        .db 00010011b
SmallA:
        .db 5
        .db 00000000b
        .db 00001100b
        .db 00010110b
        .db 00011110b
        .db 00010110b
        .db 00010110b
        .db 00000000b
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