Apple | IIgs | Apple II Technical Note #26

Apple II
Technical Notes
Developer Technical Support
Apple IIGS
#26: ROM Revision Summary
Revised by: Matt Deatherage
Written by: Rilla Reynolds
September 1989
October 1987
This Technical Note summarizes revisions to the Apple IIGS ROM.
Changes since November 1988: Revised to cover ROM 3.
Apple currently supports two configurations of the Apple IIGS ROM, ROM 1 and ROM
3. In August 1989, Apple IIGS computers began shipping with a 256K ROM, referred to
as version 3 or ROM 3 (ROM 2 was skipped since there was already enough confusion
about the first version, ROM 0, and the second version, ROM 1). System Software
continues to support ROM 1, but it no longer supports ROM 0. Authorized Apple dealers
can upgrade older systems (i.e., machines with serial numbers lower than E704…) to
ROM 1 upon request.
ROM 1 requires System Software 2.0 or later, while ROM 3 requires System Software
5.0 or later. Although applications may work using older system software releases, they
may not function properly due to the coordination of system software and ROM
Changes from ROM 0 to ROM 1
• Absolute ADB devices are now supported correctly.
• ADB fatal system error code is now $0911 instead of $0400.
• ADBReset routine now delays about 160 microseconds before reading the buttons.
• ADBStatus TRUE is now $FFFF instead of $0001.
• All ADB error codes now include the tool number.
• SRQrmv no longer crashes when you make the call with a command pending.
AppleDisk 3.5
• AppleDisk 3.5 Macintosh block reads and writes now work as documented.
• Extended status call now returns bit 0 = 1 if AppleDisk 3.5 media has been switched
since the last READ, WRITE, or FORMAT.
Apple II Technical Notes
• New AppleDisk 3.5 status calls have been implemented to get internal variable and
work buffer starting addresses.
• Link Access Protocol (LAP) inter-packet gap now handles added SCC delay.
• Name Binding Protocol (NBP) now considers uppercase and lowercase characters
• A nonexistent protocol no longer hangs the dispatcher.
Desk Manager
• SaveScreen and RestoreScreen now work.
Event Manager
• Now auto-key events are not posted in the queue unless the queue is empty.
• EMStartUp and EMShutDown code has been optimized.
• Event Manager now returns an error instead of crashing when there is an attempt to post
an invalid event.
Integer Math
New Changes:
• Optimized the multiply routine.
RAM patches moved to ROM:
• Changes to FixMul, FixRatio, and SDivide.
• SDivide recovers from a divide by zero operation.
• New calls: FracMul, FixDiv, FracDiv, FixRound, FracSqrt, FracCos,
FracSin, FixATan2, HiWord, LoWord, Long2Fix, Fix2Long, Fix2Frac,
Frac2Fix, Fix2X, Frac2X, X2Fix, X2Frac.
Memory Manager
• Optimized Purge and Compact for banks 0 and 1 and moved from RAM to ROM.
• RAM patches and enhancements moved to ROM.
• RAMdisk now returns bytes transferred count on DIB call.
• SetHandleSize makes a handle temporarily unpurgeable while changing handle
Miscellaneous Tools
RAM patches and enhancements moved to ROM:
• AbsClamp fixes.
• Battery RAM routines work if data bank is set to a bank other than bank data is in.
Apple IIGS
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Apple II Technical Notes
• Firmware entry calls now return processor status in high byte instead of low byte.
• GetAddr with ref number $000E returns SerFlag address for SCC interrupts
(useful if not using serial firmware).
• ID manager can reuse discarded IDs.
• Keyboard interrupts now enable VBL interrupts.
• Munger now works with 1-char strings and returns with A=0.
• New SysBeep call.
• PackBytes and UnpackBytes return with A=0.
• ReadBParam and ReadBRAM error codes corrected.
• WriteBParam and WriteBRAM do not return error codes (this is a documentation
• WriteTimeHex Bad Parameter error code is now $0301.
• 80-column screens maintained if break occurs and Pascal protocol in effect.
• AppleSoft tabbing in 80-column mode now works correctly.
• Control Panel’s Maximum RAM Disk Size increased to 8128K instead of 4096K.
• Firmware version number returned is $1 instead of $0.
• Interrupts now disabled during paddle read routines.
• Interrupts re-enabled after fatal system error (for debug DAs).
• Mouse clamps with positive minimum and negative maximum works (e.g., $6000 min,
$8000 max).
• New monitor command, pound sign (#), installs monitor entry and memory peeker
classic desk accessories (unless already installed), accessible via the Control Panel.
Reinstalled automatically on reset; disabled by power off only.
• New monitor command, Control-N, clears m, e, and x bits for native mode. (Control-R
still switches to 8-bit, emulation mode.)
• RESET entry point at $00FA62 sets state register to $0C and shadow register to $08.
• Shadowing of the Super Hi-Res area in Bank 1 is no longer enabled automatically.
• WAIT routine now always exits with C=1.
QuickDraw II
RAM patches and enhancements moved to ROM:
• 640-mode pen masks now work when portRect origin not a multiple of 8.
• Arcs, ovals, and round rects can be drawn across bank boundaries.
• Changes to round drawing routines: PPToPort, GetFontLore, GetROMFont, and
• Current bank bytes 100…106 no longer modified by scaling and mapping calls.
• FontFlags 1 and 2 added for pen width and color control.
• FramePoly returns with A=0.
• GetPort returns all four bytes of GrafPort.
• HideCursor and ShowCursor work correctly with obscured cursor.
• MapRgn now works on rectangular regions.
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Apple II Technical Notes
• Pixel painting routines support QuickDraw Auxiliary Tool Set stretching and shrinking.
• PPToPort now clips correctly to the current portRect.
• QDStartUp and QDShutDown save and restore the scan line interrupt vector.
• RectInRgn bug fixed.
• ScrollRect works when the ClipRgn and VisRgn are not rectangular.
• SetSysFont works.
• StdPixels now returns with A=0 if the pen is not visible.
• Text underline bug fixed.
• TextBounds works.
New QuickDraw changes:
• Busy flag now maintained correctly by ClosePort, OffsetRgn, InsetRgn,
KillPoly, FillRect, FrameOval, PaintOval, EraseOval, InvertOval,
FillOval, FrameArc, PaintArc, EraseArc, InvertArc, FillArc,
FrameRRect, PaintRRect, EraseRRect, InvertRRect, and FillRRect.
• Cursor appears in correct Super Hi-Res mode as determined by the low byte’s bit 7
(320/640) of the MasterSCB.
• Elems now can be called from any part of memory.
• HALT exception jumping through the incorrect vector fixed.
• Integer overflow during conversion reported.
• STATUS call moved to ROM.
• Scheduler now accepts a flush function call.
• Task-handling RAM patch (on System Disk 1.0 and later) moved to ROM.
Serial I/O
• First character after an XON is no longer trashed when buffering is not enabled.
• If serial mode bit 17 = 1, parity and framing error suppression are defeated.
• Parity, baud, and data format commands work with buffering.
• STATUS call will not report that a character is ready if the character arrives with a
parity or framing error.
• STATUS call works correctly with XON/XOFF protocol.
• PR#5, following a PR#5 with I/O error (i.e., no disk in drive), now boots as expected.
• SmartPort manipulates only Slot 6 motor on detect so the IWM can run in fast mode.
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Apple II Technical Notes
• Fixed bug in FFStopSound call.
• Fixed low-level RAM read/write bug.
• Interrupts are disabled when the internal bell is active.
• Interrupts no longer need to be disabled when accessing sound RAM.
• New sound diagnostics with the following error codes: $0C001 = failed RAM data test,
$0C002 = RAM address test, $0C003 = register data test, and $0C004 = control register
• Sound Manager RAM patches and enhancements moved to ROM.
Text Tools
RAM patches moved to ROM:
• RAM patches moved to ROM for Writing and ErrorWriting routines.
• TextInit Illegal device error now is in 16-bit mode instead of 8.
Tool Locator
• Optimized tool dispatcher.
• ROM tools present on a memory expansion card are installed.
Changes from ROM 1 to ROM 3
ROM 3 is 256K (double the size of ROM 1) and contains several tools which do not exist
in ROM 1. The patch file TS3 fixes known bugs in ROM 3 which were discovered after it
was frozen. ROM 3 tools are basically System Software 5.0 tools, and the System
Software 5.0 documentation covers these tools in detail. This Note only documents nontool changes.
AppleDisk 3.5 and SmartPort
• Use new routines for all block reads to fast RAM to eliminate double buffering.
• The extended DIB status call returns the device subtype byte $C1.
• Fixed anomalies described in SmartPort Technical Note #6, Apple IIGS SmartPort
• Fixed a ROM 1 bug that caused Write Protected to be returned with higher
priority than Device Offline for the ProDOS STATUS call.
• AppleTalk moved to slots 1 and 2 from slot 7.
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Apple II Technical Notes
Control Panel CDA
• The original Options menu is now the Keyboard menu and does not contain mouse
• A new Mouse menu is present. The new keyboard microcontroller allows finer control
of mouse tracking, so a selection procedure better than yes or no is present. Parameters
are also available to set the keyboard mouse feature, which allows the numeric keypad
to emulate a mouse.
• Added an option to resize the RAM disk on the next reset in the RAM Disk menu. This
option resets to No after one reboot and resizing so the RAM disk is not accidently
reformatted on every boot thereafter.
• If slot 7 is set to AppleTalk, the Control Panel displays a warning if neither slot 1 nor
slot 2 is similarly set.
• The Printer Port and Modem Port menus now display only those parameters that may be
changed if AppleTalk is the selection for those ports.
• The RAM disk no longer has minimum and maximum settings, but rather one RAM
disk size setting.
• Enhanced memory searching commands to automatically cross bank boundaries.
• Added Step and Trace debugging functions.
• Now provide vectors for the same functionality as the GS/OS System Service calls
• Now resize the RAM disk when the system is rebooted with the Control-Open AppleShift-Reset key combination.
• Handle text page 2 shadowing and power-up bits in the new CYA chip.
• Flash the border if the sound volume is set to zero and a beep is necessary.
• In ROM 1 and earlier, the Miscellaneous Tools mouse firmware called the 8-bit mouse
routines in the $C400 space to do the work. In ROM 3, the 8-bit routines call the 16-bit
routines to read the hardware. This change effectively means those programs which use
16-bit mouse calls (including desktop applications through the Event Manager) may use
the mouse when slot 4 is set to Your Card.
• Slots 1 and 2 may now be set to Printer, Modem, AppleTalk, or Your Card. With
System Software 5.0, slot 7 does not need to be set to AppleTalk to use an AppleTalk
network, although one can do it for compatibility. There is no transparent printing
firmware in slot 7.
• The Alternate Display Mode CDA no longer sets the system to fast speed when normal
speed is selected in the Control Panel.
• Added a new command, {val}=V, to set the video screen display I/O switches when
resuming a program.
• Control-T command now works as a toggle—executing it once changes to text mode,
but now executing it again switches back to the previous video mode You may change
this saved video mode with the =V command.
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Apple II Technical Notes
• Battery RAM value $59 now controls the presence of the Visit Monitor and Memory
Peeker CDAs. If this byte has the high bit set at boot time, the CDAs are automatically
• The Monitor and Memory Peeker both allow the use of Control-X to terminate a long
display (i.e., a handle list or memory dump).
Serial I/O
• XON and XOFF are no longer sent with the high bit set when buffering is enabled.
• Terminal mode cursor is more consistent with the rest of the system.
• Extended Interface calls now return errors in the carry and the accumulator.
The following tools are now in ROM:
• Window Manager
• Menu Manager
• Control Manager
• Line Edit
• Dialog Manager
• Scrap Manager
• Font Manager
• List Manager
Further Reference
• Apple IIGS Firmware Reference
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