Chapter 6 MOUSE Services Routine ---------------------- 1. Introduction For system which supports the MOUSE, the ROM BIOS contains two mouse- related services, a PD ISR and a PD DSR (see Figure 1-1): * PD ISR The BIOS PD Interrupt Service Routine (ISR) is invoked via H/W INT 74h each time the mouse is moved or the mouse button is pressed while the mouse is enabled. PD ISR stores the PD data temporarily in the PD buffer, when it accummulates the PD data to reach the package size, it will pass a package of PD data through the system stack to the mouse driver. * PD DSR The BIOS PD Device Service Routine (DSR) is invoked via S/W INT 15h, AH=0C2h. It is different from the keyboard DSR. PD DSR provides some functions to initialize mouse, enable/disable mouse, set the mouse configurations such as sample rate, resolution ..., and so on, but it doesn't provide users access to the PD data. <ÄÄ H/W ÄÄ>³<ÄÄÄÄ BIOS Level ÄÄÄÄÄÄÄÄ>³<ÄÄÄÄÄ User's Level ÄÄÄÄÄÄÄÄÄÄÄÄ> Level PD H/W ÚÄÄÄÄÄÄÄÄ¿ ÚÄÄÄÄÄÄÄÄ¿ ÚÄÄÄÄÄÄÄÄ¿ Interrupt ³ ÃÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ>³ System ÃÄÄÄÄÄÄ>³ MOUSE ÃÄÄ> MOUSE (IRQ 12) ³ PD ISR ³ ÚÄÄÄÄÄÄÄÄÄÄÄ¿³ Stack ³ ³ Driver ³ AP ÚÄÄÄÄÄÄÄÄ>³ ³<Ä>³ PD buffer ³ÀÄÄÄÄÄÄÄÄÙ ÀÄÄÄÄÂÄÄÄÙ ³ ³ INT 74h³ ÀÄÄÄÄÄÄÄÄÄÄÄÙ ³ ³ ³ ³ ÚÄÄÄÄÄÄÄÄÄÄÄ¿ ³ ³ ³ ³<Ä>³ PD flags ³ ³ ÚÄÁÄÄ¿ ÀÄÄÄÄÄÄÄÄÙ Ú>ÀÄÄÄÄÄÄÄÄÄÄÄÙ ³ ³ PD ³<¿ ³ Extended ³ ÀÄÄÄÄÙ ³ ³ BIOS Data ³ ³ ÚÄÄÄÄÄÄÄÄ¿ ³ ³ ³ ³ ÃÄÙ ³ ³ ³ PD DSR ³ ³ ÀÄÄÄÄ´ ³ ³ ³ INT 15h³<ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ ³ AH=0C2h³ ³ ³ ÀÄÄÄÄÄÄÄÄÙ Figure 1-1. The roles of the PD ISR and PD DSR ---------------------------------------------- 2. PD ISR (INT 74h) Operation 2.1 PD H/W Architecture Please refer to Keyboard Services (Figure 2-1) for PD H/W architecture. It must use the keyboard controller 8042 to support the PS/2 MOUSE. 2.2 PD Data The data structure that PD ISR passes onto the device driver is called "package". Normally, one package contains 3 bytes as shown: 1st byte - status bit 0 - left button status - 1 : pressed bit 1 - right button status - 1 : pressed bit 2 - reserved (must be 0) bit 3 - reserved (must be 1) bit 4 - X data sign - 1 negative bit 5 - Y data sign - 1 negative bit 6 - X data overflow - 1 overflow bit 7 - Y data overflow - 1 overflow 2nd byte - X data bit 0 - least significant bit bit 7 - most significant bit 3rd byte - Y data bit 0 - least significant bit bit 7 - most significant bit 2.3 PD ISR Processing The PD ISR simply collects one package of the PD data in PD buffer, and maintains the PD flags. PD buffer and PD flags are all in the extended BIOS data area as shown: 022h device drive far call offset 024h device drive far call segment 026h pointing device flag bit 7 -- command in progress bit 6 -- resend bit 5 -- acknowledge bit 4 -- error bit 3 -- reserved = 0 bit 2-0 -- index count of input data 027h pointing device flag bit 7 -- device drive far call flag bit 6 -- Pointer device interface initialization ok bit 5-3 -- reserved bit 2-0 -- package size 028h-02Fh Pointing device buffer When PD ISR collects the PD data to reach the package size, it will pass a package of PD data through the system stack to the mouse driver. 3. PD DSR (INT 15h, AH=0C2h) Operation PD DSR initializes the mouse to function as follows: For all functions of the pointing device, the output is as follows: (cy) = 0 -- operation successfully completed = 1 -- unsuccesful operation (ah) = status 00 - no error 01 - invalid function call 02 - invalid function input 03 - error 04 - reserved 05 - no far call installed 06 - reserved ENABLE OR DISABLE POINTING DEVICE input: (ah) = c2h (al) = 0 (bh) = 0 disable the pointing device = 1 enable the pointing device > 1 Invalid function call output: See the note as described above. RESET POINTING DEVICE input: (ah) = c2h (al) = 1 output: See the note as described above. bx = device ID if operation is successful Notes: After reset, the pointing device situation is described as follows: - It is disabled unless the flag of pointing device interface initialization is set. - Sample rate at 100 reports/sec - Resolution at 4 counts/millimeter - Scaling at 1 to 1 - Package size remain unchanged SET SAMPLE RATE input: (ah) = c2h (al) = 2 (bh) = rate value = 0 - 10 reports/sec = 1 - 20 reports/sec = 2 - 40 reports/sec = 3 - 60 reports/sec = 4 - 80 reports/sec = 5 -100 reports/sec = 6 -200 reports/sec > 6 -Invalid input output: See the note as described above. SET RESOLUTION input: (ah) = c2h (al) = 3 (bh) - resolution value = 0 - 1 count /mm = 1 - 2 counts/mm = 2 - 4 counts/mm = 3 - 8 counts/mm > 3 - Invalid input output: See the note as described above. READ DEVICE TYPE input: (ah) = c2h (al) = 4 output: See the note as described above. If operation is successfully completed then (bh) = device ID INITIALIZATION input: (ah) = c2h (al) = 5 (bh) - data package size = 1 - 1 byte = 2 - 2 bytes = 3 - 3 bytes = 4 - 4 bytes = 5 - 5 bytes = 6 - 6 bytes = 7 - 7 bytes = 8 - 8 bytes > 8 - Invalid input output: See the note as described above. The pointing device state is as follows: . Disabled . Sample rate at 100 reports/sec . Resolution at 4 counts/millimeter . Scaling at 1 to 1 EXTENDED COMMAND input: (ah) = c2h (al) = 6 (bh) = 0 return status output: See the note as described above. If operation is successfully completed then (bl) - status byte 1 bit 7 = 0 - reserved bit 6 = 0 - stream mode = 1 - remote mode bit 5 = 1 - pointer enable bit 4 = 0 - 1:1 scaling = 1 - 2:1 scaling bit 3 = 0 - reserved bit 2 = 1 - left butten pressed bit 1 = 0 - reserved bit 0 = 1 - right butten pressed (cl) - status byte 2 00 - 1 count /mm 01 - 2 counts/mm 02 - 4 counts/mm 03 - 8 counts/mm (dl) - status byte 3 0a - 10 reports/sec 14 - 20 reports/sec 2b - 40 reports/sec 3c - 60 reports/sec 50 - 80 reports/sec 64 -100 reports/sec c8 -200 reports/sec input: (ah) = c2h (al) = 6 (bh) = 1 set scaling to 1:1 output: See the note as described above. input: (ah) = c2h (al) = 6 (bh) = 2 set scaling to 2:1 output: See the note as described above. input: (ah) = c2h (al) = 6 (bh) > 2 Illegal function call output: See the note as described above. DEVICE DRIVER FAR CALL input: (ah) = c2h (al) = 7 (es) = segment pointer (bx) = offset pointer output: none