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io_copyio(9r)
NAME
  io_copyio - General: Copies data from bus address space to bus address
  space

SYNOPSIS
  int io_copyio(
	  io_handle_t srcaddr,
	  io_handle_t destaddr,
	  u_long byte_count );

ARGUMENTS
  srcaddr
      Specifies an I/O handle that you can use to reference a device register
      or memory located in bus address space (either I/O space or memory
      space). For io_copyio, this I/O handle identifies the location in bus
      address space where the copy originates. You can perform standard C
      mathematical operations (addition and subtraction only) on the I/O
      handle.  For example, you can add an offset to or subtract an offset
      from the I/O handle.

  destaddr
      Specifies an I/O handle that you can use to reference a device register
      or memory located in bus address space (either I/O space or memory
      space). In this case, the I/O handle identifies the location in bus
      address space where the copy occurs.

  byte_count
      Specifies the number of bytes in the data block to be copied.  The
      interface assumes that the buffer associated with the data block is
      physically contiguous.

DESCRIPTION
  The io_copyio interface copies data from one location in bus address space
  to another location in bus address space. The I/O handles you pass to
  srcaddr and destaddr identify the locations in bus address space where the
  copy originates and where the copy occurs. The io_copyio interface assumes
  no alignment of data associated with srcaddr and destaddr.

NOTES
  The io_copyio interface is a generic interface that maps to a bus- and
  machine-specific interface that actually performs the copy of data from one
  location in bus address space to another location in bus address space.
  Using io_copyio to perform the copy operation makes the device driver more
  portable across different CPU architectures and different CPU types within
  the same architecture.




CAUTIONS
  The I/O handles that you pass to the srcaddr and destaddr arguments of the
  io_copyio interface must be I/O handles that reference addresses residing
  in sparse space. All Alpha CPUs support sparse space. As a result, all bus
  configuration code should supply an I/O handle that references bus address
  space.

  If you pass I/O handles to the srcaddr and destaddr arguments that
  reference addresses residing in some other space (for example, dense space)
  the results of the copy operation are unpredictable.

  Tru64 UNIX provides the following interfaces that allow device drivers to
  perform copy operations and zero blocks of memory on addresses that reside
  in dense space:

    ·  bcopy

       Copies a series of bytes with a specified limit

    ·  blkclr and bzero

       Zeros a block of memory

    ·  copyin

       Copies data from a user address space to a kernel address space

    ·  copyinstr

       Copies a null-terminated string from a user address space to a kernel
       address space

    ·  copyout

       Copies data from a kernel address space to a user address space

    ·  copyoutstr

       Copies a null-terminated string from a kernel address space to a user
       address space

EXAMPLE
  See Writing Device Drivers: Tutorial for a code example of the io_copyio
  interface.

RETURN VALUES
  Upon successful completion, io_copyio returns IOA_OKAY. It returns the
  value -1 on failure.

SEE ALSO
  Kernel Interfaces: io_copyin(9r), io_copyout(9r)

Index for Section 9

Alphabetical listing for I

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