The system variables can be found for CP/M-86 1.1 (only) by BDOS function 49. This returns ES:BX pointing to an area of memory:
Offset Size Description ============================================================================ 00 DWORD DMA address 04 BYTE Current drive 05 BYTE Current user 06 WORD Directory entry number (used in Search Next) 08 BYTE Length of search when looking for filenames 09 WORD FCB for Search Next 0B WORD Segment of FCB for Search Next 0D WORD Offset of sector buffer for current drive? 0F BYTE Unknown; controls how memory is freed at program termination 10 BYTE Unused? 11 BYTE 0FFh if the BDOS is in a disc or printer call, else 0 12 DWORD Unused? 16 BYTE Control-P flag - nonzero to echo output to the printer 17 BYTE CCP drive 18 5 Unused? 1D BYTE Time: hours, BCD 1E BYTE Time: minutes, BCD 1F BYTE Time: seconds, BCD 20 3 Day, 0-terminated ASCII 23 3 Month, 0-terminated ASCII 26 3 Year mod 100, 0-terminated ASCII 29 3 Hours, 0-terminated ASCII 2C 3 Minutes, 0-terminated ASCII 2F 3 Seconds, 0-terminated ASCII 32 0Eh Text to print on status line? 40 BYTE Screen width ===============================================================================Return to the archive listing
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