search for: get_shift_key

...rupts */ + cld /* increment direction for relocation operation */ +relocate: + movw $_start, %di /* destination address for relocation */ + movw $(512/2), %cx /* number of words to relocate */ + rep; movsw /* repeat the move CX times, incrementing SI and DI after each move */ + + ljmpw $0, $get_shift_keys /* far jump to ensure CS:IP are set correctly to 0000:0600+get_shift_keys */ + /* 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 */ + movb $0x02, %ah /* function: g...

...rupts */ + cld /* increment direction for relocation operation */ +relocate: + movw $_start, %di /* destination address for relocation */ + movw $(512/2), %cx /* number of words to relocate */ + rep; movsw /* repeat the move CX times, incrementing SI and DI after each move */ + + ljmpw $0, $get_shift_keys /* far jump to ensure CS:IP are set correctly to 0000:0600+get_shift_keys */ + /* 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 */ + movb $0x02, %ah /* function: g...

...rupts */ + cld /* increment direction for relocation operation */ +relocate: + movw $_start, %di /* destination address for relocation */ + movw $(512/2), %cx /* number of words to relocate */ + rep; movsw /* repeat the move CX times, incrementing SI and DI after each move */ + + ljmpw $0, $get_shift_keys /* far jump to ensure CS:IP are set correctly to 0000:0600+get_shift_keys */ + /* 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 memo...

...number is to be forced due to Ctrl key being pressed */ pushw %es /* es:di -> $PnP header */ pushw %di pushw %dx /* dl -> drive number */ @@ -82,6 +83,15 @@ _start: ljmpw $0, $next next: + /* Provide a way 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;...