rom/kernel/getsystemattr.c

   1 #include <aros/kernel.h>
   2 #include <exec/execbase.h>
   3 #include <proto/exec.h>
   4
   5 #include <kernel_base.h>
   6
   7 #ifndef IRQ_TIMER
   8 #define IRQ_TIMER -1
   9 #endif
  10
  11 /*****************************************************************************
  12
  13     NAME */
  14 #include <proto/kernel.h>
  15
  16 AROS_LH1(intptr_t, KrnGetSystemAttr,
  17
  18 /*  SYNOPSIS */
  19         AROS_LHA(uint32_t, id, D0),
  20
  21 /*  LOCATION */
  22         struct KernelBase *, KernelBase, 29, Kernel)
  23
  24 /*  FUNCTION
  25         Get value of internal system attributes.
  26         Currently defined attributes are:
  27
  28           KATTR_Architecture [.G] (char *)        - Name of architecture the kernel built for.
  29           KATTR_VBlankEnable [SG] (unsigned char) - Enable or disable exec VBlank emulation by kernel.resource.
  30                                                     This can be needed for timer.device implementations for
  31                                                     systems with only one timer available. In this case timer.device
  32                                                     should shut off kernel's VBlank emulation before taking over the
  33                                                     timer and drive exec VBlank itself.
  34           KATTR_TimerIRQ     [.G] (int)           - Number of high precision periodic timer IRQ to be used by timer.device.
  35                                                     Needed if kernel.resource provides a timer which runs at frequency
  36                                                     which is multiple of VBlank. Generic timer.device may use this IRQ
  37                                                     for improved accuracy. Frequency of this timer is specified in
  38                                                     SysBase->ex_EClockFrequency.
  39
  40     INPUTS
  41         id - ID of the attribute to get
  42
  43     RESULT
  44         Value of the attribute
  45
  46     NOTES
  47         These attributes (except KATTR_Architecture) are of very limited use for end user software.
  48         They are valid only in certain system states. For example KATTR_TimerPeriod goes meaningless
  49         if timer.device has taken over the system timer. These attributes are provided for system
  50         components themselves, so it's better to stay away from them.
  51
  52     EXAMPLE
  53
  54     BUGS
  55
  56     SEE ALSO
  57         KrnSetSystemAttr()
  58
  59     INTERNALS
  60
  61 ******************************************************************************/
  62 {
  63     AROS_LIBFUNC_INIT
  64
  65     switch (id)
  66     {
  67     case KATTR_Architecture:
  68         return (intptr_t)AROS_ARCHITECTURE;
  69
  70     case KATTR_VBlankEnable:
  71         return KernelBase->kb_VBlankEnable;
  72
  73     case KATTR_TimerIRQ:
  74         return IRQ_TIMER;
  75
  76     default:
  77         return -1;
  78     }
  79
  80     AROS_LIBFUNC_EXIT
  81 }