Category : Files from Magazines
Archive   : DDJ0292.ZIP
Filename : 386BSD.292

.po 0
[LISTING ONE]


/* [Excerpted from /sys/i386/include/param.h] */
...
#ifndef __ORPL__
/* Interrupt Group Masks */
extern u_short __highmask__; /* interrupts masked with splhigh() */
extern u_short __ttymask__; /* interrupts masked with spltty() */
extern u_short __biomask__; /* interrupts masked with splbio() */
extern u_short __netmask__; /* interrupts masked with splimp() */
extern u_short __protomask__; /* interrupts masked with splnet() */
extern u_short __nonemask__; /* interrupts masked with splnone() */

asm(" .set IO_ICU1, 0x20 ; .set IO_ICU2, 0xa0 ");

/* adjust priority level to disable a group of interrupts */
#define __ORPL__(m) ({ u_short oldpl, msk; \
msk = (msk); \
asm volatile (" \
cli ; /* modify interrupts atomically */ \
movw %1, %%dx ; /* get mask to OR in */ \
inb $ IO_ICU1+1, %%al ; /* get low order mask */ \
xchgb %%dl, %%al ; /* switch the old with the new */ \
orb %%dl, %%al ; /* finally, OR both it in! */ \
outb %%al, $ IO_ICU1+1 ; /* and stuff it back where it came */ \
inb $ 0x84, %%al ; /* post it & handle write recovery */ \
inb $ IO_ICU2+1, %%al ; /* next, get high order mask */ \
xchgb %%dh, %%al ; /* switch the old with the new */ \
orb %%dh, %%al ; /* finally, or it in! */ \
outb %%al, $ IO_ICU2+1 ; /* and stuff it back where it came */ \
inb $ 0x84, %%al ; /* post it & handle write recovery */ \
movw %%dx, %0 ; /* return old mask */ \
sti /* allow interrupts again */ " \
: "&=g" (oldpl) /* return values */ \
: "g" ((m)) /* arguments */ \
: "ax", "dx" /* registers used */ \
); \
oldpl; /* return the "old" value */ \
})
/* force priority mask to a set value */
#define __SETPL__(m) ({ u_short oldpl, msk; \
msk = (msk); \
asm volatile (" \
cli ; /* modify interrupts atomically */ \
movw %1, %%dx ; /* get mask to OR in */ \
inb $ IO_ICU1+1, %%al ; /* get low order mask */ \
xchgb %%dl, %%al ; /* switch the old with the new */ \
outb %%al, $ IO_ICU1+1 ; /* and stuff it back where it came */ \
inb $ 0x84, %%al ; /* post it & handle write recovery */ \
inb $ IO_ICU2+1, %%al ; /* next, get high order mask */ \
xchgb %%dh, %%al ; /* switch the old with the new */ \
outb %%al, $ IO_ICU2+1 ; /* and stuff it back where it came */ \
inb $ 0x84, %%al ; /* post it & handle write recovery */ \
movw %%dx, %0 ; /* return old mask */ \
sti /* allow interrupts again */ " \
: "&=g" (oldpl) /* return values */ \
: "g" ((m)) /* arguments */ \
: "ax", "dx" /* registers used */ \
); \
oldpl; /* return the "old" value */ \
})
#define splhigh() __ORPL__(__highmask__)
#define spltty() __ORPL__(__ttymask__)
#define splbio() __ORPL__(__biomask__)
#define splimp() __ORPL__(__netmask__)
#define splnet() __ORPL__(__protomask__)
#define splsoftclock() __ORPL__(__protomask__)
#define splx(v) ({ u_short val; \
val = (v); \
if (val == __nonemask__) (void) spl0(); /* zero is special */ \
else (void) __SETPL__(val); \
})
#endif __ORPL__
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