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diff --git a/bsp_howto/ada95_interrupt.rst b/bsp_howto/ada95_interrupt.rst index 4bf61d3..f6fc0fc 100644 --- a/bsp_howto/ada95_interrupt.rst +++ b/bsp_howto/ada95_interrupt.rst @@ -1,81 +1,75 @@ .. comment SPDX-License-Identifier: CC-BY-SA-4.0 +.. COMMENT: COPYRIGHT (c) 1988-2008. +.. COMMENT: On-Line Applications Research Corporation (OAR). +.. COMMENT: All rights reserved. + Ada95 Interrupt Support ####################### Introduction ============ -This chapter describes what is required to enable Ada interrupt -and error exception handling when using GNAT over RTEMS. +This chapter describes what is required to enable Ada interrupt and error +exception handling when using GNAT over RTEMS. -The GNAT Ada95 interrupt support RTEMS was developed by -Jiri Gaisler <jgais@ws.estec.esa.nl> who also wrote this -chapter. +The GNAT Ada95 interrupt support RTEMS was developed by Jiri Gaisler +<jgais@ws.estec.esa.nl> who also wrote this chapter. Mapping Interrupts to POSIX Signals =================================== -In Ada95, interrupts can be attached with the interrupt_attach pragma. -For most systems, the gnat run-time will use POSIX signal to implement -the interrupt handling, mapping one signal per interrupt. For interrupts -to be propagated to the attached Ada handler, the corresponding signal -must be raised when the interrupt occurs. +In Ada95, interrupts can be attached with the interrupt_attach pragma. For +most systems, the gnat run-time will use POSIX signal to implement the +interrupt handling, mapping one signal per interrupt. For interrupts to be +propagated to the attached Ada handler, the corresponding signal must be raised +when the interrupt occurs. -The same mechanism is used to generate Ada error exceptions. -Three error exceptions are defined: program, constraint and storage -error. These are generated by raising the predefined signals: SIGILL, -SIGFPE and SIGSEGV. These signals should be raised when a spurious -or erroneous trap occurs. +The same mechanism is used to generate Ada error exceptions. Three error +exceptions are defined: program, constraint and storage error. These are +generated by raising the predefined signals: SIGILL, SIGFPE and SIGSEGV. These +signals should be raised when a spurious or erroneous trap occurs. -To enable gnat interrupt and error exception support for a particular -BSP, the following has to be done: +To enable gnat interrupt and error exception support for a particular BSP, the +following has to be done: -# Write an interrupt/trap handler that will raise the corresponding - signal depending on the interrupt/trap number. +- Write an interrupt/trap handler that will raise the corresponding signal + depending on the interrupt/trap number. -# Install the interrupt handler for all interrupts/traps that will be - handled by gnat (including spurious). +- Install the interrupt handler for all interrupts/traps that will be handled + by gnat (including spurious). -# At startup, gnat calls ``__gnat_install_handler()``. The BSP - must provide this function which installs the interrupt/trap handlers. +- At startup, gnat calls ``__gnat_install_handler()``. The BSP must provide + this function which installs the interrupt/trap handlers. -Which CPU-interrupt will generate which signal is implementation -defined. There are 32 POSIX signals (1 - 32), and all except the -three error signals (SIGILL, SIGFPE and SIGSEGV) can be used. I -would suggest to use the upper 16 (17 - 32) which do not -have an assigned POSIX name. +Which CPU-interrupt will generate which signal is implementation defined. There +are 32 POSIX signals (1 - 32), and all except the three error signals (SIGILL, +SIGFPE and SIGSEGV) can be used. I would suggest to use the upper 16 (17 - 32) +which do not have an assigned POSIX name. -Note that the pragma interrupt_attach will only bind a signal -to a particular Ada handler - it will not unmask the -interrupt or do any other things to enable it. This have to be -done separately, typically by writing various device register. +Note that the pragma interrupt_attach will only bind a signal to a particular +Ada handler - it will not unmask the interrupt or do any other things to enable +it. This have to be done separately, typically by writing various device +register. Example Ada95 Interrupt Program =============================== -An example program (``irq_test``) is included in the -Ada examples package to show how interrupts can be handled -in Ada95. Note that generation of the test interrupt -(``irqforce.c``) is BSP specific and must be edited. +An example program (``irq_test``) is included in the Ada examples package to +show how interrupts can be handled in Ada95. Note that generation of the test +interrupt (``irqforce.c``) is BSP specific and must be edited. + +.. note:: -NOTE: The ``irq_test`` example was written for the SPARC/ERC32 -BSP. + The ``irq_test`` example was written for the SPARC/ERC32 BSP. Version Requirements ==================== -With RTEMS 4.0, a patch was required to psignal.c in RTEMS -sources (to correct a bug associated to the default action of -signals 15-32). The SPARC/ERC32 RTEMS BSP includes the``gnatsupp`` subdirectory that can be used as an example +With RTEMS 4.0, a patch was required to psignal.c in RTEMS sources (to correct +a bug associated to the default action of signals 15-32). The SPARC/ERC32 +RTEMS BSP includes the``gnatsupp`` subdirectory that can be used as an example for other BSPs. -With GNAT 3.11p, a patch is required for ``a-init.c`` to invoke -the BSP specific routine that installs the exception handlers. - -.. COMMENT: COPYRIGHT (c) 1988-2008. - -.. COMMENT: On-Line Applications Research Corporation (OAR). - -.. COMMENT: All rights reserved. - +With GNAT 3.11p, a patch is required for ``a-init.c`` to invoke the BSP +specific routine that installs the exception handlers. |