search for: force_first_hard_disk

...y for the user to force boot from first hard-disk by pressing a Ctrl key */ +get_shift_keys: /* Provide a way for the user to force CHS addressing mode by pressing either Shift key */ + testb $0x04, 0x0417 /* I/O memory-mapped keyboard shift flags: control key pressed? */ + jz detect_bios_type +force_first_hard_disk: + movb $0x80, -6(%bp) /* offset from top-of-stack to drive number; force it to be first hard disk */ + movb $0x80, %dl /* change the drive number about to be used in detect_bios_type */ + +detect_bios_type: /* Check to see if we have EBIOS */ pushw %dx /* drive number */ movb $0x41, %ah /...

...ys */ + /* rather than the current CS:IP which will be based on 0x7C00 */ + +get_shift_keys: /* Provide a way for the user to force CHS addressing mode by pressing either Shift key */ + testb $0x04, 0x0417 /* I/O memory-mapped keyboard shift flags: control key pressed? */ + jz shift_test +force_first_hard_disk: + movb $0x80, -6(%bp) /* offset from top-of-stack to drive number; force it to be first hard disk */ + movb $0x80, %dl /* change the drive number about to be used in detect_bios_type */ +shift_test: + testb $0x03, 0x0417 /* left or right shift-keys pressed? */ + jnz use_chs_addressing /* if so...