Note: This IBM PC BIOS API call is for DOS/Win16 personality only. Use Family API for portability.

Note: osFree Macro Library provides macros for most of functions

2022/03/13 05:41 · prokushev · 0 Comments

Int 10H, AH=01H


IBM 5150 and higher


Set Cursor Size

osFree Macro Library

Family API


AH = 01h
CH = Start line
CL = End line




  • buggy on EGA systems–BIOS remaps cursor shape in 43 line modes, but returns unmapped cursor shape
  • UltraVision scales size to the current font height by assuming 14-line monochrome and 8-line color fonts; this call is not valid if cursor emulation has been disabled
  • applications which wish to change the cursor by programming the hardware directly on EGA or above should call INT 10/AX=1130h or read 0040h:0085h first to determine the current font height
  • on some adapters, setting the end line greater than the number of lines in the font will result in the cursor extending to the top of the next character cell on the right
  • AMI 386 BIOS and AST Premier 386 BIOS will lock up the system if AL is not equal to the current video mode