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- /* Etherboot routines for PCBIOS firmware.
- *
- * Body of routines taken from old pcbios.S
- */
-
- #include "stdint.h"
- #include "realmode.h"
- #include "compiler.h"
-
- #define BIOS_DATA_SEG 0x0040
-
- #define CF ( 1 << 0 )
-
- /**************************************************************************
- CURRTICKS - Get Time
- Use direct memory access to BIOS variables, longword 0040:006C (ticks
- today) and byte 0040:0070 (midnight crossover flag) instead of calling
- timeofday BIOS interrupt.
- **************************************************************************/
- #if defined(CONFIG_TSC_CURRTICKS)
- #undef CONFIG_BIOS_CURRTICKS
- #else
- #define CONFIG_BIOS_CURRTICKS 1
- #endif
- #if defined(CONFIG_BIOS_CURRTICKS)
- unsigned long currticks ( void ) {
- static uint32_t days = 0;
- uint32_t ticks;
- uint8_t midnight;
-
- /* Re-enable interrupts so that the timer interrupt can occur
- */
- REAL_EXEC ( rm_currticks,
- "sti\n\t"
- "nop\n\t"
- "nop\n\t"
- "cli\n\t",
- 0,
- OUT_CONSTRAINTS (),
- IN_CONSTRAINTS (),
- CLOBBER ( "eax" ) ); /* can't have an empty clobber list */
-
- get_real ( ticks, BIOS_DATA_SEG, 0x006c );
- get_real ( midnight, BIOS_DATA_SEG, 0x0070 );
-
- if ( midnight ) {
- midnight = 0;
- put_real ( midnight, BIOS_DATA_SEG, 0x0070 );
- days += 0x1800b0;
- }
- return ( days + ticks );
- }
- #endif /* CONFIG_BIOS_CURRTICKS */
-
- /**************************************************************************
- CPU_NAP - Save power by halting the CPU until the next interrupt
- **************************************************************************/
- void cpu_nap ( void ) {
- REAL_EXEC ( rm_cpu_nap,
- "sti\n\t"
- "hlt\n\t"
- "cli\n\t",
- 0,
- OUT_CONSTRAINTS (),
- IN_CONSTRAINTS (),
- CLOBBER ( "eax" ) ); /* can't have an empty clobber list */
- }
-
- #if (TRY_FLOPPY_FIRST > 0)
- /**************************************************************************
- DISK_INIT - Initialize the disk system
- **************************************************************************/
- void disk_init ( void ) {
- REAL_EXEC ( rm_disk_init,
- "sti\n\t"
- "xorw %ax,%ax\n\t"
- "movb $0x80,%dl\n\t"
- "int $0x13\n\t"
- "cli\n\t",
- 0,
- OUT_CONSTRAINTS (),
- IN_CONSTRAINTS (),
- CLOBBER ( "eax", "ebx", "ecx", "edx",
- "ebp", "esi", "edi" ) );
- }
-
- /**************************************************************************
- DISK_READ - Read a sector from disk
- **************************************************************************/
- unsigned int pcbios_disk_read ( int drive, int cylinder, int head, int sector,
- char *fixme_buf ) {
- uint16_t ax, flags, discard_c, discard_d;
- segoff_t buf = SEGOFF ( fixme_buf );
-
- /* FIXME: buf should be passed in as a segoff_t rather than a
- * char *
- */
-
- REAL_EXEC ( rm_pcbios_disk_read,
- "sti\n\t"
- "pushl %%ebx\n\t" /* Convert %ebx to %es:bx */
- "popl %%bx\n\t"
- "popl %%es\n\t"
- "movb $0x02, %%ah\n\t" /* INT 13,2 - Read disk sector */
- "movb $0x01, %%al\n\t" /* Read one sector */
- "int $0x13\n\t"
- "pushfw\n\t"
- "popw %%bx\n\t"
- "cli\n\t",
- 4,
- OUT_CONSTRAINTS ( "=a" ( ax ), "=b" ( flags ),
- "=c" ( discard_c ), "=d" ( discard_d ) ),
- IN_CONSTRAINTS ( "c" ( ( ( cylinder & 0xff ) << 8 ) |
- ( ( cylinder >> 8 ) & 0x3 ) |
- sector ),
- "d" ( ( head << 8 ) | drive ),
- "b" ( buf ) ),
- CLOBBER ( "ebp", "esi", "edi" ) );
- );
-
- return ( flags & CF ) ? ax : 0;
- }
- #endif /* TRY_FLOPPY_FIRST */
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