INT 78 - HugeRealMode Driver - GET ENTRY POINT AX = 0001h Return: ES:BX -> far call entry point (see #03788,#03803) SeeAlso: AX=0000h (Table 03787) Values for HugeRealMode Server error code: 00h successful 01h unknown function 02h A20(Address line 20) The 80286 and higher CPUs allow addresses in real mode to extend slightly beyond the one megabyte mark, which causes an incompatibility with some older programs which expect such addresses to wrap back to the beginning of the address space. For complete compatibility with the 8088, newer machines thus contain circuitry which permits the twenty-first address line (A20) to be disabled. The CPU then effectively has only twenty address lines in real mode, just as the 8088 does, and addresses which would extend beyond the one megabyte mark wrap to the beginning of the address space. See also High Memory Area, Real Mode. disabled 03h A20(Address line 20) The 80286 and higher CPUs allow addresses in real mode to extend slightly beyond the one megabyte mark, which causes an incompatibility with some older programs which expect such addresses to wrap back to the beginning of the address space. For complete compatibility with the 8088, newer machines thus contain circuitry which permits the twenty-first address line (A20) to be disabled. The CPU then effectively has only twenty address lines in real mode, just as the 8088 does, and addresses which would extend beyond the one megabyte mark wrap to the beginning of the address space. See also High Memory Area, Real Mode. enabled 04h memory allocation error 05h memory not fixeable (LOCK) 06h memory not deallocaable 07h memory not moveable (UNLOCK) 08h change in memory allocation size not possible 09h file error (with .XMF-file) 0Ah memory error (with .XMF-file) 0Bh unknown procedure (currently Turbo Pascal unit only) (Table 03788) Call HugeRealMode Server "Enable A20(Address line 20) The 80286 and higher CPUs allow addresses in real mode to extend slightly beyond the one megabyte mark, which causes an incompatibility with some older programs which expect such addresses to wrap back to the beginning of the address space. For complete compatibility with the 8088, newer machines thus contain circuitry which permits the twenty-first address line (A20) to be disabled. The CPU then effectively has only twenty address lines in real mode, just as the 8088 does, and addresses which would extend beyond the one megabyte mark wrap to the beginning of the address space. See also High Memory Area, Real Mode." function with: AL = 00h Return: AX = error code (see #03787) Note: The HugeRealMode Server requires an XMS-driver like HIMEM.SYS loaded before HUGEREAL (for XMS-memory allocation and A20(Address line 20) The 80286 and higher CPUs allow addresses in real mode to extend slightly beyond the one megabyte mark, which causes an incompatibility with some older programs which expect such addresses to wrap back to the beginning of the address space. For complete compatibility with the 8088, newer machines thus contain circuitry which permits the twenty-first address line (A20) to be disabled. The CPU then effectively has only twenty address lines in real mode, just as the 8088 does, and addresses which would extend beyond the one megabyte mark wrap to the beginning of the address space. See also High Memory Area, Real Mode. control). It utilizes some undocumentedInformation about a product which is not publicly available from the manufacturer, and must be determined by reverse-engineering (disassembly, trial-and-error, etc.). Undocumented information tends to change -- often dramatically -- between successive revisions of a product, since the manufacturer has no obligation to maintain compatibility in behavior which is not explicitly stated. 386+ features to enable 4G code and data segments (flat memory model) in the CPUs real-mode. It is not compatible with V86-mode (as with most EMM386). For maximum speed and compatibility with DOS it uses a two stage interrupt model (see #03791) SeeAlso: #03789,#03790,#03791 (Table 03789) Call HugeRealMode Server "Disable A20(Address line 20) The 80286 and higher CPUs allow addresses in real mode to extend slightly beyond the one megabyte mark, which causes an incompatibility with some older programs which expect such addresses to wrap back to the beginning of the address space. For complete compatibility with the 8088, newer machines thus contain circuitry which permits the twenty-first address line (A20) to be disabled. The CPU then effectively has only twenty address lines in real mode, just as the 8088 does, and addresses which would extend beyond the one megabyte mark wrap to the beginning of the address space. See also High Memory Area, Real Mode." function with: AL = 01h Return: AX = error code (see #03787) SeeAlso: #03788,#03790 (Table 03790) Call HugeRealMode Server "Query A20(Address line 20) The 80286 and higher CPUs allow addresses in real mode to extend slightly beyond the one megabyte mark, which causes an incompatibility with some older programs which expect such addresses to wrap back to the beginning of the address space. For complete compatibility with the 8088, newer machines thus contain circuitry which permits the twenty-first address line (A20) to be disabled. The CPU then effectively has only twenty address lines in real mode, just as the 8088 does, and addresses which would extend beyond the one megabyte mark wrap to the beginning of the address space. See also High Memory Area, Real Mode. State" function with: AL = 02h Return: AX = A20(Address line 20) The 80286 and higher CPUs allow addresses in real mode to extend slightly beyond the one megabyte mark, which causes an incompatibility with some older programs which expect such addresses to wrap back to the beginning of the address space. For complete compatibility with the 8088, newer machines thus contain circuitry which permits the twenty-first address line (A20) to be disabled. The CPU then effectively has only twenty address lines in real mode, just as the 8088 does, and addresses which would extend beyond the one megabyte mark wrap to the beginning of the address space. See also High Memory Area, Real Mode. state (0000h disabled, 0001h enabled) SeeAlso: #03788,#03789 (Table 03791) Call HugeRealMode Server "Enable Two-Stage Interrupt Model" function with: AL = 03h Return: AX = error code (see #03787) Notes: If the two stage interrupt model is disabled, the IP(Internet Protocol) The lower level (transport layer) of the TCP/IP protocol suite. See also TCP, TCP/IP. must stay below 1MB, because the high word of EIP is not saved correctly by the standard interrupt management in real mode. Routines in extended memory may only be called with interrupts disabled (only usable for very short routines). If the two stage interupt model is enabled, these conventions are not required. The outer (transparent) ISRs save the higher word of EIP in the high word of CR3 (possible modification: in memory, if this is not safe) and then invoke the standard ISRs. Because of this handling, one should use pseudo segmented code even in extended memory (64K blocks located on 64K boundaries) to avoid the misalignment of the saved EIP (in CR3). Another way is to track and realign CR3 each time when jumping over a 64K boundary in extended memory SeeAlso: #03788,#03792 (Table 03792) Call HugeRealMode Server "Disable Two-Stage Interrupt Model" function with: AL = 04h Return: AX = error code (see #03787) SeeAlso: #03788,#03791 (Table 03793) Call HugeRealMode Server "Get Segment Address Of Server-Management Range" with: AL = 05h Return: AX = error code (see #03787) ES = segment address SeeAlso: #03803 (Table 03794) Call HugeRealMode Server "Allocate Memory" function with: AL = 06h DX = length in KB Return: AX = error code (see #03787) DX = handle EBX = start address of allocated block SeeAlso: #03795,#03796 (Table 03795) Call HugeRealMode Server "Deallocate Memory" function with: AL = 07h DX = handle Return: AX = error code (see #03787) SeeAlso: #03794,#03796 (Table 03796) Call HugeRealMode Server "Modify Allocated Memory Size" function with: AL = 08h DX = handle BX = new size in KB Return: AX = error code (see #03787) EBX = new address SeeAlso: #03794,#03795 (Table 03797) Call HugeRealMode Server "Load .XMF-file" function with: AL = 09h ES:BX -> filename (see #03798) Return: AX = error code (see #03787) ECX = target address Notes: memory must be allocated before loading .XMF file format (eXtended Memory executable File format) is supported by the HugeRealMode server for easier handling of XMS-code. The utility CONFXMF converts .OBJ-files (.COM 'tiny' model) to .XMF-format SeeAlso: #03794 Format of .XMF program file header: Offset Size Description (Table 03798) 00h DWORDDoubleword; four bytes. Commonly used to hold a 32-bit segment:offset or selector:offset address. signature "XMF_" 04h WORD length of programs code 06h WORD count of 32bit addresses to relocate 08h WORD offset to code start (releative to file start) (see #03799) 0Ah WORD relocation table Note: each word contains a 16bit address, where a relocation has to be performed SeeAlso: #03797,#03799 Format of .XMF-file code header: Offset Size Description (Table 03799) 00h WORD count of exported functions 02h N PWORDs 48bit pointers (16bit segment+32bit offset) to each function (16bit segment is always zero) var start of program's code SeeAlso: #03797,#03798 (Table 03800) Call HugeRealMode Server "Set Segment Limits" function with: AL = 0Ah BL = segment limits (see #03801) Return: AX = error code (see #03787) SeeAlso: #03793 Bitfields for HugeRealMode Server segment limits: Bit(s) Description (Table 03801) 7 CS size: 1=4GB, 0=64KB 6-5 not used 4 SS size: 1=4GB, 0=64KB 3 GS size 2 FS size 1 ES size 0 DS size SeeAlso: #03800 (Table 03802) Call HugeRealMode Server "Transfer Memory From DOS To XMSsee Extended Memory Specification" function with: AL = 0Bh ES:SI = source address EDI = target address ECX = length Return: AX = error code SeeAlso: #03803 (Table 03803) Call HugeRealMode Server "Transfer Memory From XMSsee Extended Memory Specification To DOS" function with: AL = 0Ch ESI = source address ES:DI = target address ECX = length Return: AX = error code SeeAlso: #03802