From c3f22e5aeaf4d85be0fbe3419f8219418daa1788 Mon Sep 17 00:00:00 2001 From: Nero <41307858+nero@users.noreply.github.com> Date: Sat, 15 Aug 2020 21:16:50 +0000 Subject: [PATCH] remove docs --- doc/bda.txt | 83 ----------------------------------------------------- doc/ega.txt | 11 ------- 2 files changed, 94 deletions(-) delete mode 100644 doc/bda.txt delete mode 100644 doc/ega.txt diff --git a/doc/bda.txt b/doc/bda.txt deleted file mode 100644 index da7adcb..0000000 --- a/doc/bda.txt +++ /dev/null @@ -1,83 +0,0 @@ -The actual layout of the BDA is specific to the actual BIOS firmware running. -This lists is focused on what a developer can reasonably rely on. - -0000 256 Interrupt vectors -0300 256 bytes used as stack during POST -0400 word: COM1 base I/O port -0402 word: COM2 -0404 word: COM3 -0406 word: COM4 -0408 word: LPT1 base I/O port -040A word: LPT2 -040C word: LPT3 -040E word: segment addr of the EBDA (rarely LPT4) -0410 byte: equipment list flags (INT 11h, AL) - bit 0: IPL diskette installed - bit 1: math coprocessor present - bits 4-5: default VDU mode - bits 6-7: number of floppies minus one, 0 if none -0411 byte: equipment list flags (INT 11h, AH) - bit 0: dma controller present - bits 1-3: number of serial ports - bit 4: game adapter present - bit 6-7: number of printer ports -0413 word: memory size in kilobytes (INT 12h, AX) -0417 byte: key toggle states - bit 0: right shift - bit 1: left shift - bit 2: ctrl - bit 3: alt - bit 4: scroll lock - bit 5: num lock - bit 6: caps lock - but 7: insert -0418 byte: key pressed state (1 if currently held down) - bit 0: left ctrl key - bit 1: left alt key - bit 2: system key - bit 3: suspend key - bit 4: scroll lock - bit 5: num lock - bit 6: caps lock - bit 7: insert -0419 byte: when typing a character by pressing the alt key and typing its code - into the numpad, this byte holds the current numeric value -041A word: offset into the key ringbuffer, reading end -041B word: offset into the key ringbuffer, writing end -041E 16 words: key ringbuffer, holds place for 16 keypresses -043E byte: drive restore flag -043F byte: drive motor flag -0440 byte: drive motor timeout counter in 1/18th seconds -0441 byte: status of last disk operation -0442 7 bytes: status buffer for FDC -0449 byte: current VDU mode -044A byte: number of visible display columns -044C word: VDU display buffer size -044E word: offset of current VDU page in buffer -0450 8 words: 8 cursor positions for each VDU page (MSB=row, LSB=column) -0460 byte: bottom scan line for cursor (dont write) -0461 byte: top scan line for cursor (dont write) -0462 byte: active display page number -0463 word: VDU I/O address -0465 byte: VDU mode control register -0466 byte: VDU color select register -0467 dword CS:IP for 80286 return from protected mode -046C dword: time of the day in 1/18th second ticks -0470 byte: rollover flag if above surpassed 24h (FFh = rollover) -0471 byte: bit 7 is set on ctrl+numlock to indicate break condition -0472 word: soft reset flag (set and JMP 0xFFFF:0) - 1234: bypas memory tests and VDU setup - 4321: preserve memory - 5678: system suspend - 9ABC: POST loop (on IBM convertible) -0474 dword: reserved for hard disk bios -0478 byte: LPT1 timeout in half seconds -0479 byte: LPT2 -047A byte: LPT3 -047C byte: COM1 timeout in half seconds -0480 word: key ringbuffer start (from 0x400) -0482 word: key ringbuffer -0500 byte: status of INT 5: print screen - 00: no screen print in progress - 01: in progress - FF: printer failure diff --git a/doc/ega.txt b/doc/ega.txt deleted file mode 100644 index 68ee7f2..0000000 --- a/doc/ega.txt +++ /dev/null @@ -1,11 +0,0 @@ -# Enhanced Graphics Adapter - -EGA is the successor of CGA, while itself being succeeded by VGA. - -## Detection - -mov ah, 12h -mov bl, 10h -int 0x10 - -If there is an EGA (or up) display present, bl will be changed.