77 lines
2.1 KiB
C
77 lines
2.1 KiB
C
/* Etherboot routines for PCBIOS firmware.
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*
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* Body of routines taken from old pcbios.S
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*/
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#include "compiler.h"
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#include "realmode.h"
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#include "console.h"
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#define ZF ( 1 << 6 )
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/**************************************************************************
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bios_putchar - Print a character on console
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**************************************************************************/
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static void bios_putchar ( int character ) {
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REAL_EXEC ( rm_console_putc,
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"sti\n\t"
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"movb $0x0e, %%ah\n\t"
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"movl $1, %%ebx\n\t"
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"int $0x10\n\t"
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"cli\n\t",
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1,
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OUT_CONSTRAINTS ( "=a" ( character ) ),
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IN_CONSTRAINTS ( "a" ( character ) ),
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CLOBBER ( "ebx", "ecx", "edx", "ebp", "esi", "edi" ) );
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/* NOTE: %eax may be clobbered, so must be specified as an output
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* parameter, even though we don't then do anything with it.
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*/
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}
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/**************************************************************************
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bios_getchar - Get a character from console
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**************************************************************************/
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static int bios_getchar ( void ) {
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uint16_t character;
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REAL_EXEC ( rm_console_getc,
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"sti\n\t"
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"xorw %%ax, %%ax\n\t"
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"int $0x16\n\t"
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"cli\n\t",
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1,
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OUT_CONSTRAINTS ( "=a" ( character ) ),
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IN_CONSTRAINTS (),
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CLOBBER ( "ebx", "ecx", "edx", "ebp", "esi", "edi" ) );
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return ( character & 0xff );
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}
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/**************************************************************************
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bios_iskey - Check for keyboard interrupt
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**************************************************************************/
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static int bios_iskey ( void ) {
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uint16_t flags;
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REAL_EXEC ( rm_console_ischar,
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"sti\n\t"
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"movb $1, %%ah\n\t"
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"int $0x16\n\t"
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"pushfw\n\t"
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"popw %%ax\n\t"
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"cli\n\t",
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1,
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OUT_CONSTRAINTS ( "=a" ( flags ) ),
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IN_CONSTRAINTS (),
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CLOBBER ( "ebx", "ecx", "edx", "ebp", "esi", "edi" ) );
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return ( ( flags & ZF ) == 0 );
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}
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static struct console_driver bios_console __console_driver = {
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.putchar = bios_putchar,
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.getchar = bios_getchar,
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.iskey = bios_iskey,
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};
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