Amstrad Extended BIOS calls

The Amstrad extended BIOS is accessed using the USERF BIOS function. To call it, use: CALL USERF DEFW value The value is a 16-bit address in memory bank 0 (user programs normally run in bank 1). The (documented) XBIOS jumpblock starts at 0080h and runs up to 00EEh. My implementation of CP/M on the PCW16 supports calls from TE_ASK up to BANK2_RUN_ROUTINE. Since the address of USERF may vary from computer to computer, the following subroutine should be used to access it in a machine-independent way: USERF: PUSH HL PUSH DE LD HL,(1) LD DE,57h ADD HL,DE POP DE EX (SP),HL RET Frequently, these routines will require an address to be passed to them. Unless they are being called from within Bank 0, the address should be above 0C000h so that it is visible to the routine. The alternate register set is preserved during the call, but the values of the alternate registers will not be available to the called routine.

DD INIT - 0080h Initialise the floppy disc driver. When called, this resets the floppy drives to their default parameters (for 3" or 3.5" drives, depending on computer), and turns the disc motor off. Corrupts AF,BC,DE,HL. DD SETUP - 0083h Set up the floppy disc driver. Entered with: HL=address of parameter block, above 0C000h. Corrupts AF, BC, DE and HL. The parameter block is formed: DB motor on timeout, 10ths of a second DB motor off timeout, 10ths of a second DB write current off time in 10 uS units DB head settle time, milliseconds. DB step rate, milliseconds. DB head unload delay in 32ms units. DB (2*head load delay in 4ms units)+non DMA mode. [Recent PCW versions only] If HL=0, set up only one drive - the one whose number is given in C. DE holds the address of the parameter block. DD READ SECTOR - 0086h Read a floppy disc sector. Entered with: B=CP/M bank, C=disc unit(0 or 1), D=track(0 based), E=sector (0 based), HL=load address within bank, IX=address of drive XDPB. Returns: Carry set if OK, reset if error. A=error number 0-9. BC, DE and HL are corrupted. Error codes are: 0: Drive not ready 1: Write protected 2: Seek fail 3: Data error 4: No data 5: Missing address mark 6: Bad format 7: Unknown error 8: Media changed 9: Unsuitable media DD WRITE SECTOR - 0089h Write a floppy disc sector. Entered with: B=CP/M bank, C=disc unit(0 or 1), D=track(0 based), E=sector (0 based), HL=address within bank of sector, IX=address of drive XDPB. Returns: Carry set if OK, reset if error. A=error number 0-9. BC, DE and HL are corrupted. DD CHECK SECTOR - 008Ch Verify a floppy disc sector. Entered with: B=CP/M bank, C=disc unit(0 or 1), D=track(0 based), E=sector (0 based), HL=address within bank of sector, IX=address of drive XDPB. Returns: If error: Carry reset, A=error number 0-9. If no error, Carry set, Zero set if sector matched sector in memory. Otherwise Zero reset. BC, DE and HL are corrupted. DD FORMAT - 008Fh Format a floppy disc track. Entered with: B=CP/M bank, C=disc unit(0 or 1), D=track(0 based), E=filler byte, HL=address within bank of format data, IX=address of drive XDPB. Returns: If error: Carry reset, A=error number 0-9. If no error, Carry set. BC, DE and HL are corrupted. The format data area is a list of sectors; each entry occupies four bytes. The entry for a sector is laid out as: DB track number DB head number DB sector number DB physical sector shift. 0 => 128, 1 => 256, 2 => 512... DD LOGIN - 0092h Log in a floppy disc. Entered with: C=disc unit(0 or 1), IX=address of drive XDPB. Returns: If OK, carry set, A=format type, BC corrupt, DE=size of double-bit allocation vector, HL=size of hash table, XDPB initialised. If error, A=error number, BC DE HL XDPB corrupt. Format types are: 0: PCW Single Sided Single Density 1: CPC System format 2: CPC Data format 3: PCW Double Sided Double Density DD SEL FORMAT - 0095h Preload an XDPB with a standard format. Entered with: A=format IX=address of destination XDPB. Returns: If OK, carry set, A=format type, BC corrupt, DE=size of double-bit allocation vector, HL=size of hash table, XDPB initialised. If error, A=error number, BC DE HL XDPB corrupt. Format types are: 0: PCW standard SS/SD, 173k 1: CPC System format, 169k 2: CPC Data format, 180k 3: PCW standard DS/DD, 706k DD DRIVE STATUS - 0098h Get the drive status. Entered with: C=disc unit(0 or 1); bit 2 of C contains head number. Returns HL corrupt, A=uPD765a status register 3: bit 7: ? bit 6: Write protected bit 5: Ready if bits 5 and 6 are zero the drive is not present. bit 4: Track 0 bit 3: ? bit 2: Head bit 1: Unit high bit (always zero, Units 2-3 are not implemented). bit 0: Unit low bit DD READ ID - 009Bh Read a sector ID. Entered with: C=disc unit(0 or 1); D=track(0 based); IX=address of XDPB. Returns: If OK, Carry set, A=physical sector number. If error, Carry reset, A=error number. Always, BC and DE are corrupt and HL=address of FDC output buffer: DB number-of-result-bytes DB result bytes DD L DPB - 009Eh Initialise a DPB from a boot record. Entered with: HL=address of boot record. IX=address of DPB. Returns: If carry set, OK, A=disc type (as for DD LOGIN). If carry clear, A=error number. BC DE and HL are always corrupted. Note: This function always fails on the CPC6128. DD L XDPB - 00A1h Initialise an XDPB from a boot record. Entered with: HL=address of boot record. IX=address of XDPB. Returns: If carry set, OK, A=disc type (as for DD LOGIN). If carry clear, A=error number. BC DE and HL are always corrupted. Note: This function always fails on the CPC6128. DD L ON MOTOR - 00A4h Turn the floppy drive motors on. Preserves all registers and flags. Waits until the motors have spun up to speed before returning. DD L T OFF MOTOR - 00A7h Start countdown for turning the motors off. Preserves all registers and flags. DD L OFF MOTOR - 00AAh Switch the floppy drive motors off immediately. Corrupts AF, BC, DE and HL. DD L READ - 00ADh Execute a uPD765A read command. Entered with: HL=address of input buffer. DB CP/M bank DW address of data buffer within bank DW number of data bytes DB number of uPD765a command bytes DB uPD765a command bytes Returns AF, BC, DE corrupt; HL=address of results buffer: DB number of result bytes DB result bytes The floppy drive motors must be running. DD L WRITE - 00B0h Execute a uPD765A write, scan or format command. Entered with: HL=address of input buffer. DB CP/M bank DW address of data buffer within bank DW number of data bytes DB number of uPD765a command bytes DB uPD765a command bytes Returns AF, BC, DE corrupt; HL=address of results buffer: DB number of result bytes DB result bytes The floppy drive motors must be running. DD L SEEK - 00B3h Seek to a track. Entered with: C=disc unit+4*head, D=cylinder number, IX=address of XDPB. CD SA INIT - 00B6h Initialise serial port. Entered with: A=mode or command. If A is a mode, D=no. of stop bits, E=parity, H=number of receiver data bits, L=number of transmitter data bits. Corrupts AF, BC, DE and HL. Modes: 00h - No handshake 0FFh - Handshake 0FEh - Interrupt, no handshake (on Spectrum +3, behaves as 00h). 0FDh - Interrupt, handshake (on Spectrum +3, behaves as 0FFh). Commands: 80h - Drop DTR 7Fh - Raise DTR 7Eh - Drop RTS (no effect on Spectrum +3) 7Dh - Raise RTS (no effect on Spectrum +3) Number of stop bits: D=0 1 stop bit D=1 1.5 stop bits (on Spectrum +3, behaves as D=2) D=2 2 stop bits Parity: E=0 None E=1 Odd E=2 Even CD SA BAUD - 00B9h Set SIO baud rate. Entered with: H=receiver baudrate, L=transmitter baudrate. Corrupts AF, BC, DE, HL. Baud rates are numbered from 1-15; see here. CD SA PARAMS - 00BCh Get SIO parameters. Returns registers containing parameters as set by CD SA INIT. TE ASK - 00BFh Get screen size and cursor position. Returns: B=top row of viewport in physical screen coordinates on CPC6128, BC is C=left column of viewport in physical screen coordinates always zero. D=height of viewport-1 E=width of viewport-1 H=cursor row, viewport coordinates L=cursor column, viewport coordinates Implemented on the PCW16. TE RESET - 00C2h Reset the terminal emulator. Corrupts AF, BC, DE and HL. Resets viewport to full screen, character set to Language 0 (USA), no special effects, screen colours to default, cursor enabled etc. Can be called if the screen has been altered by other programs than the CRT driver. Implemented on the PCW16. TE STL ASK - 00C5h Is the status line enabled? Returns: A=0 if status line disabled, 0FFh if enabled. Zero false if status line visible, true if not visible. On the +3, the status line can be enabled and invisible. Implemented on the PCW16, though nothing is ever displayed on the status line. TE STL ON OFF - 00C8h Turn the status line on or off. Entered with: A=0 for off or 0FFh for on. Corrupts F, BC, DE, HL. The status line, if enabled, displays BIOS error messages and the status of the PCW's built-in printer. If it is disabled, BIOS error messages go to the main screen. A similar status line is used in DOS Plus, where it lists the names of programs running in the background. Implemented on the PCW16, though nothing is ever displayed on the status line. TE SET INK - 00CBh Set screen palette. Entered with: A=ink id; B=colour; C=flash value. Corrupts AF, BC, DE and HL. On the CPC, Ink 0 is the background, Ink 1 is the foreground. Other inks are not used by CP/M. The colour is a value from 0-63; the flash value is another colour. If they are different, the ink will alternate between the two. On the PCW, Ink 0 is the background, Ink 1 is the foreground. Other inks are ignored. If the colour of ink 0 is greater than the colour of ink 1, then the dark-on-light screen is used; otherwise, the light-on-dark screen. On the Spectrum +3, Ink 0 is the background and border, and Ink 1 is the foreground. The colour is a value from 0-63; if the flash value differs from the colour value, the ink is set to flash. Unlike the PCW and CPC, setting colours with this call does not change the colours already visible onscreen. On the PCW16, Ink 0 is the background, Ink 1 is the foreground. In screen mode 2, other inks are not used. In mode 1, Inks 2 and 3 are used; in mode 0, Inks 0-15 are used. Flashing is not supported. The ink number for B on the CPC, +3 and PCW16 is computed thus: Bits 0-1: Blue Bits 2-3: Red Bits 4-5: Green Bits 6-7: Ignored The RGB values are: 00 Colour is off 01 Colour is on, low intensity [CPC]/ normal intensity [Spectrum and PCW16] 10 Colour is on, normal intensity 11 Colour is on, high intensity BUG: This function does not work under PCW or +3 CP/M, because the values in B and C are always reset to zero before they are examined. TE SET BORDER - 00CEh Set screen border colour. Entered with: B=colour, as above. Corrupts AF, BC, DE and HL. On the PCW, bit 7 of B is set for reversed video (dark text on light background) and bit 6 is set if the screen is to be blank. Implemented on the PCW16. TE SET SPEED - 00D1h Set colour flash speed. Entered with: H=time spent in main colour, L=time spent in alternative colour, specified in 50ths of a second. Corrupts AF and HL. Has no effect on a Spectrum +3 or a PCW16. KM SET EXPAND - 00D4h Set a keyboard expansion string. Entered with: B=string number, 80h-9Eh; C=length of string; HL=address of string. Returns: If OK, Carry set. If string too long or B invalid, Carry clear. A, BC, DE, HL corrupted. Implemented on the PCW16. KM SET KEY - 00D7h Set what character a keypress translates to. Entered with: B=ASCII value, C=key number, D=bitmap of shift states. Corrupts AF and HL. On the PCW16, the key number is the Rosanne code corresponding to that keynumber and shift state (except for keypad keys). Special ASCII values are: PCW, PCW16 and Spectrum: 80h-9Eh: Expansion tokens 9Fh: Ignore this keypress CPC: 80h-9Fh: Expansion tokens 0FDh: Caps lock 0FEh: Shift lock 0FFh: Ignore If a bit is set in the shift states bitmap, it indicates that the table for that combination of shift keys should be modified. The bits mean: 0 - Unshifted keys 1 - SHIFT [PCW & PCW16], CAPS SHIFT [Spectrum +3] 2 - ALT [PCW], SYMBOL SHIFT [Spectrum +3], CTRL [PCW16] 3 - SHIFT+ALT [PCW], EXTEND [Spectrum +3], SHIFT+CTRL [PCW16] 4 - EXTRA [PCW], TASK [PCW16] KM KT GET - 00DAh Get a character/key number. On the CPC6128: Returns C=character, B=0. On the PCW and +3: If key pressed, returns C=key number, B=shift bitmap. If not, returns carry false, C corrupt, B=shift bitmap. Corrupts A. The shift bitmap is: Bit 0 not defined Bit 1 EXTRA Bit 2 Generated by a key repeat Bit 3 Caps lock Bit 4 Num lock Bit 5 SHIFT [PCW]; CAPS [Spectrum +3] Bit 6 Shift lock Bit 7 ALT [PCW]; SYMB [Spectrum +3] On the PCW16: If key pressed, returns C=keycode, B=Rosanne shift state. If not, returns BC corrupt. Always corrupts A. KM KT PUT - 00DDh Simulate a keypress.. Entered with: B=shift bitmap, C=key number. On the +3 and PCW, the shift bitmap is: Bit 0 not defined Bit 1 EXTRA [PCW]; EXTEND [+3] Bit 2 Generated by a key repeat Bit 3 Caps lock Bit 4 Num lock Bit 5 SHIFT [PCW]; CAPS [Spectrum +3] Bit 6 Shift lock Bit 7 ALT [PCW]; SYMB [Spectrum +3] On the CPC, this function has no effect. The main use of this function is to change the state of Caps/Num/Shift lock; use KM KT PUT to change the lock, and KM KT GET to swallow the simulated keypress. The PCW shift lock is implemented in hardware and so cannot be changed by this call. On the +3, Shift lock operates on the CAPS SHIFT key. On the PCW16, B and C are a Rosanne shift bitmap and keycode respectively. The Caps/Num/Shift locks are not implemented. KM SET SPEED - 00E0h Set the keyboard reset speed.. Entered with: H=initial delay, L=subsequent delay. Corrupts AF. Both delays are given in fiftieths of a second. 0 means 256, ie keys hardly ever repeat. The initial delay takes place before a key repeats at all; the subsequent delay takes place between further repetitions. Implemented on the PCW16. CD VERSION - 00E3h Get version numbers. Supported on the PCW16.. Returns: A=machine type, B=BIOS major version number, C=BIOS minor version number, HL=machine specific version number. Machine types are: 0 CPC6128 1 PCW8000/9000/10 series 3 Spectrum +3 65 PCW16 (65 = 'A', ie "Anne") The BIOS major version number is 2 for a PCW9512 or 9512+, 1 otherwise. On a CPC6128, the machine specific version number is the ROM version. On recent versions of PCW CP/M, H=0 and L is a bitmap of hardware detected: Bit 0: Set if the PCW is a 9256, 9512+ or 10; else reset. Bit 1: ? Bit 2: Set if a PCW9512 printer controller is not present. Bit 3: Parallel+Serial interface (CPS8256) is present. Bit 4: Set if a PCW8256 printer controller is present. Bit 5: Parallel (but no serial) interface is present. Bits 6-7: ? On earlier PCW versions this word is zero. On the PCW16, the machine specific version number is the address in bank 0 of a zero-terminated ASCII string containing the Rosanne version. CD INFO - 00E6h Get system information.. Returns: A=0FFh if second floppy drive fitted, otherwise 0; B=memory size/16k; C=0FFh if serial port present, otherwise 0; DE corrupt; HL=address of buffer table. The buffer table holds addresses of disc buffers: DB CP/M bank, 0FFh for end of table DW start DW length Implemented on the PCW16, but HL returns 0. On recent PCW versions, DE is not in fact corrupt, but holds flags for the two floppy drives (E = flags for A: D = flags for B:). The flags seem to be: 00h: Drive not present 05h: Drive is 3" 180k drive 0Ah: Drive is 3" 720k drive 2Ah: Drive is 3.5" 720k drive SCR RUN ROUTINE - 00E9h Run a routine with the screen memory visible. Entered with: BC=address of routine. DE, HL, IX and IY are passed to it. Returns BC corrupt; AF, DE, HL, IX, IY as returned by routine. This routine does not exist in CPC6128 CP/M. Instead of using: LD BC,routine CALL USERF DEFW 00E9h the routine CALL USERF DEFW routine should be used. On the Spectrum +3, the above calls have an identical effect. On the PCW, however, the screen environment is unique and can only be accessed using this function. The screen is located at: CPC: 4000h in Bank 0. PCW: 5C00h in the screen environment, with Roller-RAM at 0B600h. Spectrum: 4000h in Bank 0 (left-hand half); 4000h in Bank 2 (right-hand half). The character sets are located at: CPC: 8000h in Bank 0. PCW: 0B800h in the screen environment. Spectrum: 3000h in Bank 0 (8x8 characters) and 3800h in Bank 0 (5x8 characters). FIND FID - 00ECh Find the address of an installable device driver. Supported on the PCW16. Entered with: DE=address of name (8 characters). Returns: Carry true if driver present, HL=address of driver in bank 0 (PCW16: bank 2). Else carry false, HL corrupt. Always corrupts A,BC,DE. This routine is only present in +3 CP/M, PCW CP/M versions higher than about 1.7, and PCW16 CP/M. It should not be called otherwise! Some FID names you can try are: ^Z^Z^Z^Z^Z^Z^Z^Z This somewhat oddly-named FID (the name is 8 bytes containing 1Ah) is the Cirtech hard disc driver. It has this name because it is inserted into memory by the Cirtech boot file (HD.SYS) rather than the FID loader. It doesn't exist on disc and doesn't have a filename. HDRIVER This is Cirtech's hard disc driver if you booted from a floppy containing HDRIVER.FID. I have had to use this technique once to repair a damaged EMT file on my hard drive. MASTER Although I have never seen this, I believe this is the file which allows a PCW to act as the master computer on a LocoLink connection (with another PCW as the slave). RAMDISC Spectrum +3 RAM disc driver. SAVER PCW or Spectrum +3 screensaver. SERIAL Spectrum +3 8250 UART driver, for third-party modem interfaces ADRIVE PCW16 floppy disc driver MDRIVE PCW16 RAMdisc driver CRTPLUS PCW16 screen and keyboard driver; versions also exist for Spectrum and PCW. FID file format [PCW16] BANK2 RUN ROUTINE - 00EFh Run a routine with bank 2 visible. Entered with: BC=address of routine. DE, HL, IX and IY are passed to it. Returns BC corrupt; AF, DE, HL, IX, IY as returned by routine. This works identically to SCR RUN ROUTINE, but calls code in bank 2. PCW v1.4 extra calls The following calls are present in version 1.4 of the PCW XBIOS, and are included simply for completeness: 00ECh: Initialise the XBIOS 00EFh: Is character device B ready to input? 00F2h: Input character from device B 00F5h: Is device B ready to output? 00F8h: Output character C to device B 00FBh: Initialise device C, B=baudrate 00FEh: Display error message, ask whether to retry, ignore or cancel. 0101h: Ask user to insert the disc for A: or B:. 0104h: Output a system message. 0107h: Used by XMOVE and MOVE. PCW v1.15 extra calls The following calls are present in version 1.15 of the PCW XBIOS, and are included for completeness and for comparison with the 1.4 calls above: 00EFh: ? 00F2h: Initialise the XBIOS. 00F5h: SVC_D_CHANGED - report that the disc in drive B may have been changed. 00F8h: ? 00FBh: Display error message, ask whether to retry, ignore or cancel. 00FEh: Ask user to insert the disc for A: or B:. 0101h: Output a system message. 0104h: Used by XMOVE and MOVE.
Letzte Änderung: 4.Juni 2004