156 lines
3.6 KiB
C
156 lines
3.6 KiB
C
/* Etherboot routines for PCBIOS firmware.
|
|
*
|
|
* Body of routines taken from old pcbios.S
|
|
*/
|
|
|
|
#ifdef PCBIOS
|
|
|
|
#include "etherboot.h"
|
|
#include "realmode.h"
|
|
#include "segoff.h"
|
|
|
|
#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 = VIRTUAL(0x0040,0x006c);
|
|
uint8_t *midnight = VIRTUAL(0x0040,0x0070);
|
|
|
|
/* Re-enable interrupts so that the timer interrupt can occur
|
|
*/
|
|
RM_FRAGMENT(rm_currticks,
|
|
"sti\n\t"
|
|
"nop\n\t"
|
|
"nop\n\t"
|
|
"cli\n\t"
|
|
);
|
|
|
|
real_call ( rm_currticks, NULL, NULL );
|
|
|
|
if ( *midnight ) {
|
|
*midnight = 0;
|
|
days += 0x1800b0;
|
|
}
|
|
return ( days + *ticks );
|
|
}
|
|
#endif /* CONFIG_BIOS_CURRTICKS */
|
|
|
|
/**************************************************************************
|
|
INT15 - Call Interrupt 0x15
|
|
**************************************************************************/
|
|
int int15 ( int ax )
|
|
{
|
|
struct {
|
|
reg16_t ax;
|
|
} PACKED in_stack;
|
|
struct {
|
|
reg16_t flags;
|
|
} PACKED out_stack;
|
|
reg16_t ret_ax;
|
|
|
|
RM_FRAGMENT(rm_int15,
|
|
"sti\n\t"
|
|
"popw %ax\n\t"
|
|
"stc\n\t"
|
|
"int $0x15\n\t"
|
|
"pushf\n\t"
|
|
"cli\n\t"
|
|
);
|
|
|
|
in_stack.ax.word = ax;
|
|
ret_ax.word = real_call ( rm_int15, &in_stack, &out_stack );
|
|
|
|
/* Carry flag clear indicates function not supported */
|
|
if ( ! ( out_stack.flags.word & CF ) ) return 0;
|
|
return ret_ax.h;
|
|
}
|
|
|
|
#ifdef POWERSAVE
|
|
/**************************************************************************
|
|
CPU_NAP - Save power by halting the CPU until the next interrupt
|
|
**************************************************************************/
|
|
void cpu_nap ( void )
|
|
{
|
|
RM_FRAGMENT(rm_cpu_nap,
|
|
"sti\n\t"
|
|
"hlt\n\t"
|
|
"cli\n\t"
|
|
);
|
|
|
|
real_call ( rm_cpu_nap, NULL, NULL );
|
|
}
|
|
#endif /* POWERSAVE */
|
|
|
|
#if (TRY_FLOPPY_FIRST > 0)
|
|
/**************************************************************************
|
|
DISK_INIT - Initialize the disk system
|
|
**************************************************************************/
|
|
void disk_init ( void )
|
|
{
|
|
RM_FRAGMENT(rm_disk_init,
|
|
"sti\n\t"
|
|
"xorw %ax,%ax\n\t"
|
|
"movb $0x80,%dl\n\t"
|
|
"int $0x13\n\t"
|
|
"cli\n\t"
|
|
);
|
|
|
|
real_call ( rm_disk_init, NULL, NULL );
|
|
}
|
|
|
|
/**************************************************************************
|
|
DISK_READ - Read a sector from disk
|
|
**************************************************************************/
|
|
unsigned int pcbios_disk_read ( int drive, int cylinder, int head, int sector,
|
|
char *buf ) {
|
|
struct {
|
|
reg16_t ax;
|
|
reg16_t cx;
|
|
reg16_t dx;
|
|
segoff_t buffer;
|
|
} PACKED in_stack;
|
|
struct {
|
|
reg16_t flags;
|
|
} PACKED out_stack;
|
|
reg16_t ret_ax;
|
|
|
|
RM_FRAGMENT(rm_pcbios_disk_read,
|
|
"sti\n\t"
|
|
"popw %ax\n\t"
|
|
"popw %cx\n\t"
|
|
"popw %dx\n\t"
|
|
"popw %bx\n\t"
|
|
"popw %es\n\t"
|
|
"int $0x13\n\t"
|
|
"pushfw\n\t"
|
|
"cli\n\t"
|
|
);
|
|
|
|
in_stack.ax.h = 2; /* INT 13,2 - Read disk sector */
|
|
in_stack.ax.l = 1; /* Read one sector */
|
|
in_stack.cx.h = cylinder & 0xff;
|
|
in_stack.cx.l = ( ( cylinder >> 8 ) & 0x3 ) | sector;
|
|
in_stack.dx.h = head;
|
|
in_stack.dx.l = drive;
|
|
in_stack.buffer.segment = SEGMENT ( buf );
|
|
in_stack.buffer.offset = OFFSET ( buf );
|
|
ret_ax.word = real_call ( rm_pcbios_disk_read, &in_stack, &out_stack );
|
|
return ( out_stack.flags.word & CF ) ? ret_ax.word : 0;
|
|
}
|
|
#endif /* TRY_FLOPPY_FIRST */
|
|
|
|
#endif /* PCBIOS */
|