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Annotation of coherent/b/kernel/i386/vio.s, revision 1.1.1.1

1.1       root        1: /      vio.s
                      2: 
                      3: / This code was dropped in favor of a simpler implementation.
                      4: / I am keeping it around in case I need a similar call gate interface
                      5: / some day. - hws
                      6: 
                      7: / Ring 0 services for video
                      8: / this routine is a stub for the ring 0 code
                      9: /
                     10: /      int vio(int a1, int a2, int a3)
                     11:        .globl  vio
                     12: vio:
                     13:        pushf                   / irpts off during trip to ring 0
                     14:        cli
                     15: 
                     16:        movl    16(%esp),%eax   / fetch a3
                     17:        pushl   %eax
                     18:        movl    16(%esp),%eax   / fetch a2
                     19:        pushl   %eax
                     20:        movl    16(%esp),%eax   / fetch a1
                     21:        pushl   %eax
                     22: 
                     23:        lcall   $SEG_VIO,$0     / gate to viofR0
                     24:        / viofR0 will delete 12 bytes of stack args
                     25:        popf                    / re-enable interrupts, if they were on before
                     26:        ret
                     27: 
                     28: / Ring 0 video services.  Called via a gate.
                     29: / Want interrupts off when we arrive since the interrupt gates
                     30: / lead into Ring 1.
                     31: /
                     32: / I/O map manipulations affect bitmap in tss.
                     33: / I/O map offsets are in bytes from start of map.
                     34: /
                     35: / a1:  VIO_OR_IO       bitwise or a2 into 32-bit word at offset a3
                     36: /   return the new word value stored back into the io map.
                     37: / a1:  VIO_AND_IO      bitwise and a2 into 32-bit word at offset a3
                     38: /   return the new word value stored back into the io map.
                     39: viofR0:
                     40:        enter   $0,$8   / 8 bytes of auto storage
                     41: 
                     42:        pushl   12(%ebp)        / print a1
                     43:        call    print32
                     44:        popl    %eax
                     45: 
                     46:        pushl   16(%ebp) / print a2
                     47:        call    print32
                     48:        popl    %eax
                     49: 
                     50:        pushl   20(%ebp) / print a3
                     51:        call    print32
                     52:        popl    %eax
                     53: 
                     54:        xorl    %eax,%eax
                     55:        movl    20(%ebp),%ecx   / fetch a3
                     56:        cmpl    $0,%ecx         / don't allow access to tss below iomap
                     57:        jl      vioNfg
                     58: 
                     59:        cmpl    $TSS_MAPLEN,%ecx / or above iomap
                     60:        jge     vioNfg
                     61: 
                     62:        movl    tss+TSS_IOMAP(%ecx),%eax
                     63:        pushl   %eax
                     64:        call    print32
                     65:        popl    %eax
                     66: 
                     67: vioNfg:
                     68:        cmpb    $0,12(%ebp)     / look at a1
                     69:        jnz     vioAnd
                     70:        orl     16(%ebp),%eax   / or a2 with %eax
                     71:        jmp     vioDone
                     72: 
                     73: vioAnd:
                     74:        andl    16(%ebp),%eax   / and a2 with %eax
                     75: 
                     76: vioDone:
                     77:        leave
                     78:        / make 12-byte arg list disappear
                     79:        lret    $12
                     80: 

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