56 lines
1.5 KiB
C
56 lines
1.5 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 <stdint.h>
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#include <realmode.h>
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#include <bios.h>
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#define CF ( 1 << 0 )
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/**************************************************************************
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CURRTICKS - Get Time
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Use direct memory access to BIOS variables, longword 0040:006C (ticks
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today) and byte 0040:0070 (midnight crossover flag) instead of calling
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timeofday BIOS interrupt.
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**************************************************************************/
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#if defined(CONFIG_TSC_CURRTICKS)
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#undef CONFIG_BIOS_CURRTICKS
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#else
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#define CONFIG_BIOS_CURRTICKS 1
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#endif
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#if defined(CONFIG_BIOS_CURRTICKS)
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unsigned long currticks ( void ) {
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static uint32_t days = 0;
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uint32_t ticks;
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uint8_t midnight;
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/* Re-enable interrupts so that the timer interrupt can occur
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*/
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__asm__ __volatile__ ( REAL_CODE ( "sti\n\t"
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"nop\n\t"
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"nop\n\t"
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"cli\n\t" ) : : );
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get_real ( ticks, BDA_SEG, 0x006c );
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get_real ( midnight, BDA_SEG, 0x0070 );
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if ( midnight ) {
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midnight = 0;
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put_real ( midnight, BDA_SEG, 0x0070 );
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days += 0x1800b0;
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}
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return ( days + ticks );
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}
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#endif /* CONFIG_BIOS_CURRTICKS */
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/**************************************************************************
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CPU_NAP - Save power by halting the CPU until the next interrupt
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**************************************************************************/
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void cpu_nap ( void ) {
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__asm__ __volatile__ ( REAL_CODE ( "sti\n\t"
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"hlt\n\t"
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"cli\n\t" ) : : );
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}
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