https://zeta.asie.pl/wiki/ 2026-04-03T21:48:34+00:00 https://zeta.asie.pl/wiki/ https://zeta.asie.pl/wiki/lib/exe/fetch.php?media=wiki:logo.png text/html 2021-12-25T15:10:50+00:00 Anonymous (anonymous@undisclosed.example.com) https://zeta.asie.pl/wiki/doku.php?id=jdm:pc9801:biosmem&rev=1640445050&do=diff NEC PC-9801 - BIOS Memory Map TODO Address Description 0x401 Extended memory between 0x100000 and 0xFFFFFF, in units of 128 KB 0x43B bit 2 - 0 if memory hole between 15 and 16MB present, 1 otherwise; TODO 0x501 BIOS flags: bits 0-2 - conventional memory size, in units of 128 KB; bit 3 - 1 if high resolution system; bits 4-6 TODO; bit 7 - 1 if 2.4576MHz timer; 0 if 1.9968MHz timer text/html 2021-12-25T12:30:24+00:00 Anonymous (anonymous@undisclosed.example.com) https://zeta.asie.pl/wiki/doku.php?id=jdm:pc9801:int1ch&rev=1640435424&do=diff NEC PC-9801 - INT 1Ch AH = 00h - Get System Time Input: * AH = 00h * ES:BX = data buffer Output: * buffer[0] = year (in two-digit BCD) * buffer[1] = month (in BCD) * buffer[2] = day (in BCD) * buffer[3] = hour (in BCD) * buffer[4] = minute (in BCD) text/html 2022-02-18T22:44:19+00:00 Anonymous (anonymous@undisclosed.example.com) https://zeta.asie.pl/wiki/doku.php?id=jdm:pc9801:int18h&rev=1645224259&do=diff NEC PC-9801 - INT 18h AH = 00h - Get Keystroke Input: * AH = 00h Output: * AX = keystroke The keystroke is removed from the input buffer. TODO: Blocks until a keystroke is received? AH = 01h - Check Keystroke Input: * AH = 01h Output: text/html 2022-02-18T22:36:48+00:00 Anonymous (anonymous@undisclosed.example.com) https://zeta.asie.pl/wiki/doku.php?id=jdm:pc9801:ports&rev=1645223808&do=diff NEC PC-9801 - I/O Ports 02h TODO 35h TODO 37h TODO 71h TODO 73h TODO 77h TODO 7Ch (GRCG - Control) * bit 7 - enable (1)/disable (0) GRCG * bit 6 - enable (1)/disable (0) read/modify/write mode * bit 4-5 - select plane exposed to CPU (0-3) text/html 2021-12-25T15:06:35+00:00 Anonymous (anonymous@undisclosed.example.com) https://zeta.asie.pl/wiki/doku.php?id=jdm:pc9801:start&rev=1640444795&do=diff NEC PC-9801 * I/O Ports * BIOS Memory Map * Text Mode Interrupts * INT 07h * INT 08h * INT 18h - Keyboard/Video * INT 19h - Serial * INT 1Ah - Printer * INT 1Bh - Disk * INT 1Ch - Timer text/html 2021-12-25T15:17:37+00:00 Anonymous (anonymous@undisclosed.example.com) https://zeta.asie.pl/wiki/doku.php?id=jdm:pc9801:textmode&rev=1640445457&do=diff NEC PC-9801 - Text mode Screen layout By default, video memory is stored at A000h:offset for characters and A200h:offset for attributes - both are stored as 16-bit words. Attribute bits * bit 0 - rendered (1), hidden (0) * bit 1 - blink (1) *