List of AArch32 affected SWIs (changes)

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List of AArch32 affected SWIs

This list is from a survey as part of Addressing the end-of-life of AArch32.

OS (Kernel and FileSwitch)

OS_Word 0 (Read line)

• Subreason has 2 byte pointer to the input buffer. This SWI is already of limited use on 32b memory map as the buffer must reside between &8000 and &FFFF
• No changes proposed

OS_Word 16? (Econet transmit)

• Has (unaligned!) 4 byte pointers to start/end of data
• Currently translated by BBCEconet into the corresponding Econet SWIs

OS_Word 17? (Econet open or receive)

• Has (unaligned!) 4 byte pointers to start/end of data
• Currently translated by BBCEconet into the corresponding Econet SWIs

OS_Word 21 (Define pointer shape)

• Has 4 byte pointer to pointer shape data

OS_Word 22 (Write screen base address)

• Has 4 byte pointer to screen

OS_FSControl 26 (Copy objects)

• Optional information descriptor in R8 has 4 byte pointer to a buffer

OS_ChangeEnvironment handler 6 (Error handler)

• The block has a 32b PC at offset 0

OS_ChangeEnvironment handler 7 (Callback handler)

• The block has space for 16×32b register dump

OS_ChangeEnvironment handler 8 (BreakPoint handler)

• The block has space for 16×32b register dump

OS_ReadArgs

• The output buffer uses 32b pointers to parsed args

OS_DelinkApplication and OS_RelinkApplication

• Vector buffer uses 12 bytes per vector
• The format is opaque to the caller but internally the address of the vector routines are stored as 3×4 byte parameters

OS_HeapSort[32]

• Pointer arrays for sort type >= 2 are 32b each

OS_ReadMemMapEntries and OS_SetMemMapEntries and OS_FindMemMapEntries

• The logical address in the returned table is 32b

OS_Memory 0 (General page block operations)

• The page block uses 32b logical address

OS_IICOp

• Block word 1 is a pointer to the buffer to transfer, but is 32b

OS_Hardware

• The HAL device descriptors include several absolute function pointers and pointers to description strings which are 32b

OS_SpriteOp 52 and OS_SpriteOp 56 and OS_SpriteOp 65

• When a Colour Mapping Descriptor is used in R7 the block passed contains a 32b workspace and function pointer
• Pixel translation tables for 4k/32k/64k colours have a 32b table pointer trapped between two ‘32K.’ or ‘32K+’ guard words

Econet

• Immediate operation Econet_JSR branches to a 32b address received via Econet, optionally to AArch32 code that follows it in the immediate buffer.
• This is true of both the Econet (native) and NetI (over IP)

Window Manager

Wimp_AutoScroll

• The state change handler at block + 24 uses a 32b function pointer to a routine

Wimp_DragBox

• Drag types 8-11 have 32b function pointers to user routines at block + 40 onwards

Wimp_Poll 13 (Pollword non-zero)

• The poll block includes a 32b pointer to the pollword at block + 0

Wimp icon blocks include 32b pointers to sprite areas or validation strings overloaded with the 12 byte icon data.
Wimp menu blocks can include a 32b pointer to a submenu at offset +4 of the menu item data.

Sound (Level 0)

Sound_Configure

• The first 4 words of the Channel Handler (R3) are absolute pointers to tables and routines
• The first word of the Scheduler (R4) is a pointer to the scheduler code

Podule Manager

Podule_ReadInfo?

• Some returned quantities (1, 4, 8, 9, 13, 14, 15, 18, 19, 20, 23, 24, 25, 29) are pointers in a 32b address space

FPEmulator

FPEmulator_Abort

• The register dump pointed to by the returned R0 assumes a 32b integer register set.

FileCore

FileCore_MiscOp 6 (Read processed FileCore_Create block)

• Although it returns a copy of the FileCore_Create block which only uses offsets, and therefore is in itself OK assuming the maximum module size isn’t changed, this SWI has turned the 32b offsets into absolute addresses.

FileCore_DiscOp[64]

• Scatter lists are pairs of 32b memory/disc addresses

Draw

Draw path block code 1 is a 32b continuation path block pointer. There are plenty of spare code numbers to assign a new one for 64b pointers.

MessageTrans

MessageTrans_MakeMenus

• A 32b submenu pointer appears in the menu block as noted for the Window Manager’s menu blocks

Drag An Object

DragAnObject_Start

• The register block pointed to by R2 (loaded into registers for the renderer) assumes 4B per register

Task Manager

TaskManager_EnumerateTasks

• The returned block for each task includes a 32b pointer to the task name

Territory Manager

Territory_Register

• This SWI expects a table of 32b function pointers to communicate with the territory

DMA Manager

DMA_RegisterChannel

• The 5 word block in R4 contains function pointers to 5 control routines for the channel

DMA_QueueTransfer

• The scatterlist of transfers provided include 32b logical address/length pairs

Colour Picker

ColourPicker_OpenDialogue

• The colour picker block at +4 includes a 32b pointer to the dialogue title

Remote Printer Support

RemotePrinterSupport_EnumerateUSBPrinters?

• The returned linked list of printer descriptors is linked via 32b pointers

Mime Map

MimeMap_Translate?

• For output type MMM_TYPE_DOT_EXTNS the result is an array of pointers to extensions, where the pointers are limited to 32b

SharedSound

SharedSound_InstallHandler

• Passes a fill handler table which contains 2×32b function pointers to fill routines

SharedSound_InstallDriver

• Passes a driver table which contains 6×32b function ti driver routines

PCI

PCI_ReadInfo

• Some returned items (10, 16) are pointers in a 32b address space, the SWI is modelled on Podule_ReadInfo? which is similarly affected

CompressPNG

CompressPNG_Start?

• Parameter items 1 (add text comment), 5 (add palette data), 6 (add transparency data) include 32b pointers to the respective item

URL

URL_ParseURL

• Returns a block of 10×32b pointers at R5 to the elements of the broken down URL

SDIODriver

SDIO_Op

• When bit 26 is set uses a scatter list of pairs of 32b memory/disc addresses, like FileCore

PDumperSupport

PDumperSupport_Claim?/PDumperSupport_Free?/PDumperSupport_Find?

• The pointer to an anchor word in R0 is actually a 32b linked list pointer, though the list format isn’t publically documented so could be changed to a larger pointer with minimal impact

VideoOverlay

VideoOverlay_MapBuffer

• Returns a buffer list in R0 which includes 32b logical addresses in the block

SharedCLibrary

SharedCLibrary_LibInit[_A|_R|Module|APCS_32|ModuleAPCS_32]

• All affected in as far as the stubs supplied in R0 are 32b per entry and encoded as a MOV pc,#0 instruction, which are then changed to LDR pc,table_entry_N after init (OK since AArch64 instructions are 32b as well), but the table_entry_N which follows only has space for 32b branch addresses.

Resolver

Resolver_GetHost? and Resolver_GetHostByName?

• Return a hostent structure containing arrays of pointers, and pointers to the host name which are 32b in size

ATA (aka SATADriver)

ATA_Op

• Uses 32b address/length pair scatter lists in R3, like FileCore

ATA_PacketOp?

• Uses 32b address/length pair scatter lists in R3, like FileCore

USBDriver

USBDriver_RegisterBus

• Uses a table of method pointers in R0 when the host controller registers with the USB stack

USBDriver_InsertTransfer

• Takes a pointer to a usbd_xfer structure which includes a number of 32b pointers

USBDriver_TransferComplete

• Takes a pointer to a usbd_xfer structure which includes a number of 32b pointers

USBDriver_ScheduleSoftInterrupt

• Takes a pointer to a usbd_bus structure which includes a number of 32b pointers

DCI drivers (Ether, PPP, EconetA)

Driver Information Blocks (DIB) include pointers to the name, address, module, and location which are 32b in size and surrounded by other structure members. Pointers to DIBs also appear in registers for Service_DCIFrameTypeFree and Service_DCIDriverStatus.

The transmit SWI also uses an mbuf chain which has 32 bit linked list pointers in it (see notes on MBuf Manager).