/* cpu.h * * This include file contains information pertaining to the XXX * processor. * * COPYRIGHT (c) 1989-1999. * On-Line Applications Research Corporation (OAR). * * The license and distribution terms for this file may be * found in the file LICENSE in this distribution or at * http://www.rtems.com/license/LICENSE. * * $Id$ */ #ifndef __CPU_h #define __CPU_h #ifdef __cplusplus extern "C" { #endif #include /* pick up machine definitions */ #ifndef ASM #include #endif /* conditional compilation parameters */ /* * Should the calls to _Thread_Enable_dispatch be inlined? * * If TRUE, then they are inlined. * If FALSE, then a subroutine call is made. * * Basically this is an example of the classic trade-off of size * versus speed. Inlining the call (TRUE) typically increases the * size of RTEMS while speeding up the enabling of dispatching. * [NOTE: In general, the _Thread_Dispatch_disable_level will * only be 0 or 1 unless you are in an interrupt handler and that * interrupt handler invokes the executive.] When not inlined * something calls _Thread_Enable_dispatch which in turns calls * _Thread_Dispatch. If the enable dispatch is inlined, then * one subroutine call is avoided entirely.] * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ #define CPU_INLINE_ENABLE_DISPATCH FALSE /* * Should the body of the search loops in _Thread_queue_Enqueue_priority * be unrolled one time? In unrolled each iteration of the loop examines * two "nodes" on the chain being searched. Otherwise, only one node * is examined per iteration. * * If TRUE, then the loops are unrolled. * If FALSE, then the loops are not unrolled. * * The primary factor in making this decision is the cost of disabling * and enabling interrupts (_ISR_Flash) versus the cost of rest of the * body of the loop. On some CPUs, the flash is more expensive than * one iteration of the loop body. In this case, it might be desirable * to unroll the loop. It is important to note that on some CPUs, this * code is the longest interrupt disable period in RTEMS. So it is * necessary to strike a balance when setting this parameter. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ #define CPU_UNROLL_ENQUEUE_PRIORITY TRUE /* * Does RTEMS manage a dedicated interrupt stack in software? * * If TRUE, then a stack is allocated in _ISR_Handler_initialization. * If FALSE, nothing is done. * * If the CPU supports a dedicated interrupt stack in hardware, * then it is generally the responsibility of the BSP to allocate it * and set it up. * * If the CPU does not support a dedicated interrupt stack, then * the porter has two options: (1) execute interrupts on the * stack of the interrupted task, and (2) have RTEMS manage a dedicated * interrupt stack. * * If this is TRUE, CPU_ALLOCATE_INTERRUPT_STACK should also be TRUE. * * Only one of CPU_HAS_SOFTWARE_INTERRUPT_STACK and * CPU_HAS_HARDWARE_INTERRUPT_STACK should be set to TRUE. It is * possible that both are FALSE for a particular CPU. Although it * is unclear what that would imply about the interrupt processing * procedure on that CPU. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ #define CPU_HAS_SOFTWARE_INTERRUPT_STACK FALSE /* * Does this CPU have hardware support for a dedicated interrupt stack? * * If TRUE, then it must be installed during initialization. * If FALSE, then no installation is performed. * * If this is TRUE, CPU_ALLOCATE_INTERRUPT_STACK should also be TRUE. * * Only one of CPU_HAS_SOFTWARE_INTERRUPT_STACK and * CPU_HAS_HARDWARE_INTERRUPT_STACK should be set to TRUE. It is * possible that both are FALSE for a particular CPU. Although it * is unclear what that would imply about the interrupt processing * procedure on that CPU. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ #define CPU_HAS_HARDWARE_INTERRUPT_STACK TRUE /* * Does RTEMS allocate a dedicated interrupt stack in the Interrupt Manager? * * If TRUE, then the memory is allocated during initialization. * If FALSE, then the memory is allocated during initialization. * * This should be TRUE is CPU_HAS_SOFTWARE_INTERRUPT_STACK is TRUE * or CPU_INSTALL_HARDWARE_INTERRUPT_STACK is TRUE. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ #define CPU_ALLOCATE_INTERRUPT_STACK TRUE /* * Does the RTEMS invoke the user's ISR with the vector number and * a pointer to the saved interrupt frame (1) or just the vector * number (0)? * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ #define CPU_ISR_PASSES_FRAME_POINTER 0 /* * Does the CPU have hardware floating point? * * If TRUE, then the RTEMS_FLOATING_POINT task attribute is supported. * If FALSE, then the RTEMS_FLOATING_POINT task attribute is ignored. * * If there is a FP coprocessor such as the i387 or mc68881, then * the answer is TRUE. * * The macro name "NO_CPU_HAS_FPU" should be made CPU specific. * It indicates whether or not this CPU model has FP support. For * example, it would be possible to have an i386_nofp CPU model * which set this to false to indicate that you have an i386 without * an i387 and wish to leave floating point support out of RTEMS. * * The CPU_SOFTWARE_FP is used to indicate whether or not there * is software implemented floating point that must be context * switched. The determination of whether or not this applies * is very tool specific and the state saved/restored is also * compiler specific. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ #if ( NO_CPU_HAS_FPU == 1 ) #define CPU_HARDWARE_FP TRUE #else #define CPU_HARDWARE_FP FALSE #endif #define CPU_SOFTWARE_FP FALSE /* * Are all tasks RTEMS_FLOATING_POINT tasks implicitly? * * If TRUE, then the RTEMS_FLOATING_POINT task attribute is assumed. * If FALSE, then the RTEMS_FLOATING_POINT task attribute is followed. * * So far, the only CPUs in which this option has been used are the * HP PA-RISC and PowerPC. On the PA-RISC, The HP C compiler and * gcc both implicitly used the floating point registers to perform * integer multiplies. Similarly, the PowerPC port of gcc has been * seen to allocate floating point local variables and touch the FPU * even when the flow through a subroutine (like vfprintf()) might * not use floating point formats. * * If a function which you would not think utilize the FP unit DOES, * then one can not easily predict which tasks will use the FP hardware. * In this case, this option should be TRUE. * * If CPU_HARDWARE_FP is FALSE, then this should be FALSE as well. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ #define CPU_ALL_TASKS_ARE_FP TRUE /* * Should the IDLE task have a floating point context? * * If TRUE, then the IDLE task is created as a RTEMS_FLOATING_POINT task * and it has a floating point context which is switched in and out. * If FALSE, then the IDLE task does not have a floating point context. * * Setting this to TRUE negatively impacts the time required to preempt * the IDLE task from an interrupt because the floating point context * must be saved as part of the preemption. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ #define CPU_IDLE_TASK_IS_FP FALSE /* * Should the saving of the floating point registers be deferred * until a context switch is made to another different floating point * task? * * If TRUE, then the floating point context will not be stored until * necessary. It will remain in the floating point registers and not * disturned until another floating point task is switched to. * * If FALSE, then the floating point context is saved when a floating * point task is switched out and restored when the next floating point * task is restored. The state of the floating point registers between * those two operations is not specified. * * If the floating point context does NOT have to be saved as part of * interrupt dispatching, then it should be safe to set this to TRUE. * * Setting this flag to TRUE results in using a different algorithm * for deciding when to save and restore the floating point context. * The deferred FP switch algorithm minimizes the number of times * the FP context is saved and restored. The FP context is not saved * until a context switch is made to another, different FP task. * Thus in a system with only one FP task, the FP context will never * be saved or restored. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ #define CPU_USE_DEFERRED_FP_SWITCH TRUE /* * Does this port provide a CPU dependent IDLE task implementation? * * If TRUE, then the routine _CPU_Thread_Idle_body * must be provided and is the default IDLE thread body instead of * _CPU_Thread_Idle_body. * * If FALSE, then use the generic IDLE thread body if the BSP does * not provide one. * * This is intended to allow for supporting processors which have * a low power or idle mode. When the IDLE thread is executed, then * the CPU can be powered down. * * The order of precedence for selecting the IDLE thread body is: * * 1. BSP provided * 2. CPU dependent (if provided) * 3. generic (if no BSP and no CPU dependent) * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ #define CPU_PROVIDES_IDLE_THREAD_BODY TRUE /* * Does the stack grow up (toward higher addresses) or down * (toward lower addresses)? * * If TRUE, then the grows upward. * If FALSE, then the grows toward smaller addresses. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ #define CPU_STACK_GROWS_UP TRUE /* * The following is the variable attribute used to force alignment * of critical RTEMS structures. On some processors it may make * sense to have these aligned on tighter boundaries than * the minimum requirements of the compiler in order to have as * much of the critical data area as possible in a cache line. * * The placement of this macro in the declaration of the variables * is based on the syntactically requirements of the GNU C * "__attribute__" extension. For example with GNU C, use * the following to force a structures to a 32 byte boundary. * * __attribute__ ((aligned (32))) * * NOTE: Currently only the Priority Bit Map table uses this feature. * To benefit from using this, the data must be heavily * used so it will stay in the cache and used frequently enough * in the executive to justify turning this on. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ #define CPU_STRUCTURE_ALIGNMENT /* * Define what is required to specify how the network to host conversion * routines are handled. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ #define CPU_HAS_OWN_HOST_TO_NETWORK_ROUTINES FALSE #define CPU_BIG_ENDIAN TRUE #define CPU_LITTLE_ENDIAN FALSE /* * The following defines the number of bits actually used in the * interrupt field of the task mode. How those bits map to the * CPU interrupt levels is defined by the routine _CPU_ISR_Set_level(). * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ #define CPU_MODES_INTERRUPT_MASK 0x00000001 /* * Processor defined structures * * Examples structures include the descriptor tables from the i386 * and the processor control structure on the i960ca. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ /* may need to put some structures here. */ /* * Contexts * * Generally there are 2 types of context to save. * 1. Interrupt registers to save * 2. Task level registers to save * * This means we have the following 3 context items: * 1. task level context stuff:: Context_Control * 2. floating point task stuff:: Context_Control_fp * 3. special interrupt level context :: Context_Control_interrupt * * On some processors, it is cost-effective to save only the callee * preserved registers during a task context switch. This means * that the ISR code needs to save those registers which do not * persist across function calls. It is not mandatory to make this * distinctions between the caller/callee saves registers for the * purpose of minimizing context saved during task switch and on interrupts. * If the cost of saving extra registers is minimal, simplicity is the * choice. Save the same context on interrupt entry as for tasks in * this case. * * Additionally, if gdb is to be made aware of RTEMS tasks for this CPU, then * care should be used in designing the context area. * * On some CPUs with hardware floating point support, the Context_Control_fp * structure will not be used or it simply consist of an array of a * fixed number of bytes. This is done when the floating point context * is dumped by a "FP save context" type instruction and the format * is not really defined by the CPU. In this case, there is no need * to figure out the exact format -- only the size. Of course, although * this is enough information for RTEMS, it is probably not enough for * a debugger such as gdb. But that is another problem. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ typedef struct { unsigned32 some_integer_register; unsigned32 some_system_register; } Context_Control; typedef struct { double some_float_register; } Context_Control_fp; typedef struct { unsigned32 special_interrupt_register; } CPU_Interrupt_frame; /* * The following table contains the information required to configure * the XXX processor specific parameters. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ typedef struct { void (*pretasking_hook)( void ); void (*predriver_hook)( void ); void (*postdriver_hook)( void ); void (*idle_task)( void ); boolean do_zero_of_workspace; unsigned32 idle_task_stack_size; unsigned32 interrupt_stack_size; unsigned32 extra_mpci_receive_server_stack; void * (*stack_allocate_hook)( unsigned32 ); void (*stack_free_hook)( void* ); /* end of fields required on all CPUs */ } rtems_cpu_table; /* * Macros to access required entires in the CPU Table are in * the file rtems/system.h. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ /* * Macros to access NO_CPU specific additions to the CPU Table * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ /* There are no CPU specific additions to the CPU Table for this port. */ /* * This variable is optional. It is used on CPUs on which it is difficult * to generate an "uninitialized" FP context. It is filled in by * _CPU_Initialize and copied into the task's FP context area during * _CPU_Context_Initialize. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ SCORE_EXTERN Context_Control_fp _CPU_Null_fp_context; /* * On some CPUs, RTEMS supports a software managed interrupt stack. * This stack is allocated by the Interrupt Manager and the switch * is performed in _ISR_Handler. These variables contain pointers * to the lowest and highest addresses in the chunk of memory allocated * for the interrupt stack. Since it is unknown whether the stack * grows up or down (in general), this give the CPU dependent * code the option of picking the version it wants to use. * * NOTE: These two variables are required if the macro * CPU_HAS_SOFTWARE_INTERRUPT_STACK is defined as TRUE. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ SCORE_EXTERN void *_CPU_Interrupt_stack_low; SCORE_EXTERN void *_CPU_Interrupt_stack_high; /* * With some compilation systems, it is difficult if not impossible to * call a high-level language routine from assembly language. This * is especially true of commercial Ada compilers and name mangling * C++ ones. This variable can be optionally defined by the CPU porter * and contains the address of the routine _Thread_Dispatch. This * can make it easier to invoke that routine at the end of the interrupt * sequence (if a dispatch is necessary). * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ SCORE_EXTERN void (*_CPU_Thread_dispatch_pointer)(); /* * Nothing prevents the porter from declaring more CPU specific variables. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ /* XXX: if needed, put more variables here */ /* * The size of the floating point context area. On some CPUs this * will not be a "sizeof" because the format of the floating point * area is not defined -- only the size is. This is usually on * CPUs with a "floating point save context" instruction. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ #define CPU_CONTEXT_FP_SIZE sizeof( Context_Control_fp ) /* * Amount of extra stack (above minimum stack size) required by * MPCI receive server thread. Remember that in a multiprocessor * system this thread must exist and be able to process all directives. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ #define CPU_MPCI_RECEIVE_SERVER_EXTRA_STACK 0 /* * This defines the number of entries in the ISR_Vector_table managed * by RTEMS. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ #define CPU_INTERRUPT_NUMBER_OF_VECTORS 32 #define CPU_INTERRUPT_MAXIMUM_VECTOR_NUMBER (CPU_INTERRUPT_NUMBER_OF_VECTORS - 1) /* * This is defined if the port has a special way to report the ISR nesting * level. Most ports maintain the variable _ISR_Nest_level. */ #define CPU_PROVIDES_ISR_IS_IN_PROGRESS FALSE /* * Should be large enough to run all RTEMS tests. This insures * that a "reasonable" small application should not have any problems. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ #define CPU_STACK_MINIMUM_SIZE (1024*4) /* * CPU's worst alignment requirement for data types on a byte boundary. This * alignment does not take into account the requirements for the stack. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ #define CPU_ALIGNMENT 8 /* * This number corresponds to the byte alignment requirement for the * heap handler. This alignment requirement may be stricter than that * for the data types alignment specified by CPU_ALIGNMENT. It is * common for the heap to follow the same alignment requirement as * CPU_ALIGNMENT. If the CPU_ALIGNMENT is strict enough for the heap, * then this should be set to CPU_ALIGNMENT. * * NOTE: This does not have to be a power of 2 although it should be * a multiple of 2 greater than or equal to 2. The requirement * to be a multiple of 2 is because the heap uses the least * significant field of the front and back flags to indicate * that a block is in use or free. So you do not want any odd * length blocks really putting length data in that bit. * * On byte oriented architectures, CPU_HEAP_ALIGNMENT normally will * have to be greater or equal to than CPU_ALIGNMENT to ensure that * elements allocated from the heap meet all restrictions. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ #define CPU_HEAP_ALIGNMENT CPU_ALIGNMENT /* * This number corresponds to the byte alignment requirement for memory * buffers allocated by the partition manager. This alignment requirement * may be stricter than that for the data types alignment specified by * CPU_ALIGNMENT. It is common for the partition to follow the same * alignment requirement as CPU_ALIGNMENT. If the CPU_ALIGNMENT is strict * enough for the partition, then this should be set to CPU_ALIGNMENT. * * NOTE: This does not have to be a power of 2. It does have to * be greater or equal to than CPU_ALIGNMENT. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ #define CPU_PARTITION_ALIGNMENT CPU_ALIGNMENT /* * This number corresponds to the byte alignment requirement for the * stack. This alignment requirement may be stricter than that for the * data types alignment specified by CPU_ALIGNMENT. If the CPU_ALIGNMENT * is strict enough for the stack, then this should be set to 0. * * NOTE: This must be a power of 2 either 0 or greater than CPU_ALIGNMENT. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ #define CPU_STACK_ALIGNMENT 0 /* * ISR handler macros */ /* * Support routine to initialize the RTEMS vector table after it is allocated. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ #define _CPU_Initialize_vectors() /* * Disable all interrupts for an RTEMS critical section. The previous * level is returned in _level. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ #define _CPU_ISR_Disable( _isr_cookie ) \ { \ (_isr_cookie) = 0; /* do something to prevent warnings */ \ } /* * Enable interrupts to the previous level (returned by _CPU_ISR_Disable). * This indicates the end of an RTEMS critical section. The parameter * _level is not modified. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ #define _CPU_ISR_Enable( _isr_cookie ) \ { \ } /* * This temporarily restores the interrupt to _level before immediately * disabling them again. This is used to divide long RTEMS critical * sections into two or more parts. The parameter _level is not * modified. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ #define _CPU_ISR_Flash( _isr_cookie ) \ { \ } /* * Map interrupt level in task mode onto the hardware that the CPU * actually provides. Currently, interrupt levels which do not * map onto the CPU in a generic fashion are undefined. Someday, * it would be nice if these were "mapped" by the application * via a callout. For example, m68k has 8 levels 0 - 7, levels * 8 - 255 would be available for bsp/application specific meaning. * This could be used to manage a programmable interrupt controller * via the rtems_task_mode directive. * * The get routine usually must be implemented as a subroutine. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ #define _CPU_ISR_Set_level( new_level ) \ { \ } unsigned32 _CPU_ISR_Get_level( void ); /* end of ISR handler macros */ /* Context handler macros */ /* * Initialize the context to a state suitable for starting a * task after a context restore operation. Generally, this * involves: * * - setting a starting address * - preparing the stack * - preparing the stack and frame pointers * - setting the proper interrupt level in the context * - initializing the floating point context * * This routine generally does not set any unnecessary register * in the context. The state of the "general data" registers is * undefined at task start time. * * NOTE: This is_fp parameter is TRUE if the thread is to be a floating * point thread. This is typically only used on CPUs where the * FPU may be easily disabled by software such as on the SPARC * where the PSR contains an enable FPU bit. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ #define _CPU_Context_Initialize( _the_context, _stack_base, _size, \ _isr, _entry_point, _is_fp ) \ { \ } /* * This routine is responsible for somehow restarting the currently * executing task. If you are lucky, then all that is necessary * is restoring the context. Otherwise, there will need to be * a special assembly routine which does something special in this * case. Context_Restore should work most of the time. It will * not work if restarting self conflicts with the stack frame * assumptions of restoring a context. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ #define _CPU_Context_Restart_self( _the_context ) \ _CPU_Context_restore( (_the_context) ); /* * The purpose of this macro is to allow the initial pointer into * a floating point context area (used to save the floating point * context) to be at an arbitrary place in the floating point * context area. * * This is necessary because some FP units are designed to have * their context saved as a stack which grows into lower addresses. * Other FP units can be saved by simply moving registers into offsets * from the base of the context area. Finally some FP units provide * a "dump context" instruction which could fill in from high to low * or low to high based on the whim of the CPU designers. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ #define _CPU_Context_Fp_start( _base, _offset ) \ ( (void *) _Addresses_Add_offset( (_base), (_offset) ) ) /* * This routine initializes the FP context area passed to it to. * There are a few standard ways in which to initialize the * floating point context. The code included for this macro assumes * that this is a CPU in which a "initial" FP context was saved into * _CPU_Null_fp_context and it simply copies it to the destination * context passed to it. * * Other models include (1) not doing anything, and (2) putting * a "null FP status word" in the correct place in the FP context. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ #define _CPU_Context_Initialize_fp( _destination ) \ { \ *((Context_Control_fp *) *((void **) _destination)) = _CPU_Null_fp_context; \ } /* end of Context handler macros */ /* Fatal Error manager macros */ /* * This routine copies _error into a known place -- typically a stack * location or a register, optionally disables interrupts, and * halts/stops the CPU. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ #define _CPU_Fatal_halt( _error ) \ { \ } /* end of Fatal Error manager macros */ /* Bitfield handler macros */ /* * This routine sets _output to the bit number of the first bit * set in _value. _value is of CPU dependent type Priority_Bit_map_control. * This type may be either 16 or 32 bits wide although only the 16 * least significant bits will be used. * * There are a number of variables in using a "find first bit" type * instruction. * * (1) What happens when run on a value of zero? * (2) Bits may be numbered from MSB to LSB or vice-versa. * (3) The numbering may be zero or one based. * (4) The "find first bit" instruction may search from MSB or LSB. * * RTEMS guarantees that (1) will never happen so it is not a concern. * (2),(3), (4) are handled by the macros _CPU_Priority_mask() and * _CPU_Priority_bits_index(). These three form a set of routines * which must logically operate together. Bits in the _value are * set and cleared based on masks built by _CPU_Priority_mask(). * The basic major and minor values calculated by _Priority_Major() * and _Priority_Minor() are "massaged" by _CPU_Priority_bits_index() * to properly range between the values returned by the "find first bit" * instruction. This makes it possible for _Priority_Get_highest() to * calculate the major and directly index into the minor table. * This mapping is necessary to ensure that 0 (a high priority major/minor) * is the first bit found. * * This entire "find first bit" and mapping process depends heavily * on the manner in which a priority is broken into a major and minor * components with the major being the 4 MSB of a priority and minor * the 4 LSB. Thus (0 << 4) + 0 corresponds to priority 0 -- the highest * priority. And (15 << 4) + 14 corresponds to priority 254 -- the next * to the lowest priority. * * If your CPU does not have a "find first bit" instruction, then * there are ways to make do without it. Here are a handful of ways * to implement this in software: * * - a series of 16 bit test instructions * - a "binary search using if's" * - _number = 0 * if _value > 0x00ff * _value >>=8 * _number = 8; * * if _value > 0x0000f * _value >=8 * _number += 4 * * _number += bit_set_table[ _value ] * * where bit_set_table[ 16 ] has values which indicate the first * bit set * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ #define CPU_USE_GENERIC_BITFIELD_CODE TRUE #define CPU_USE_GENERIC_BITFIELD_DATA TRUE #if (CPU_USE_GENERIC_BITFIELD_CODE == FALSE) #define _CPU_Bitfield_Find_first_bit( _value, _output ) \ { \ (_output) = 0; /* do something to prevent warnings */ \ } #endif /* end of Bitfield handler macros */ /* * This routine builds the mask which corresponds to the bit fields * as searched by _CPU_Bitfield_Find_first_bit(). See the discussion * for that routine. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ #if (CPU_USE_GENERIC_BITFIELD_CODE == FALSE) #define _CPU_Priority_Mask( _bit_number ) \ ( 1 << (_bit_number) ) #endif /* * This routine translates the bit numbers returned by * _CPU_Bitfield_Find_first_bit() into something suitable for use as * a major or minor component of a priority. See the discussion * for that routine. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ #if (CPU_USE_GENERIC_BITFIELD_CODE == FALSE) #define _CPU_Priority_bits_index( _priority ) \ (_priority) #endif /* end of Priority handler macros */ /* functions */ /* * _CPU_Initialize * * This routine performs CPU dependent initialization. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ void _CPU_Initialize( rtems_cpu_table *cpu_table, void (*thread_dispatch) ); /* * _CPU_ISR_install_raw_handler * * This routine installs a "raw" interrupt handler directly into the * processor's vector table. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ void _CPU_ISR_install_raw_handler( unsigned32 vector, proc_ptr new_handler, proc_ptr *old_handler ); /* * _CPU_ISR_install_vector * * This routine installs an interrupt vector. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ void _CPU_ISR_install_vector( unsigned32 vector, proc_ptr new_handler, proc_ptr *old_handler ); /* * _CPU_Install_interrupt_stack * * This routine installs the hardware interrupt stack pointer. * * NOTE: It need only be provided if CPU_HAS_HARDWARE_INTERRUPT_STACK * is TRUE. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ void _CPU_Install_interrupt_stack( void ); /* * _CPU_Thread_Idle_body * * This routine is the CPU dependent IDLE thread body. * * NOTE: It need only be provided if CPU_PROVIDES_IDLE_THREAD_BODY * is TRUE. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ void _CPU_Thread_Idle_body( void ); /* * _CPU_Context_switch * * This routine switches from the run context to the heir context. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ void _CPU_Context_switch( Context_Control *run, Context_Control *heir ); /* * _CPU_Context_restore * * This routine is generally used only to restart self in an * efficient manner. It may simply be a label in _CPU_Context_switch. * * NOTE: May be unnecessary to reload some registers. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ void _CPU_Context_restore( Context_Control *new_context ); /* * _CPU_Context_save_fp * * This routine saves the floating point context passed to it. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ void _CPU_Context_save_fp( void **fp_context_ptr ); /* * _CPU_Context_restore_fp * * This routine restores the floating point context passed to it. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ void _CPU_Context_restore_fp( void **fp_context_ptr ); /* The following routine swaps the endian format of an unsigned int. * It must be static because it is referenced indirectly. * * This version will work on any processor, but if there is a better * way for your CPU PLEASE use it. The most common way to do this is to: * * swap least significant two bytes with 16-bit rotate * swap upper and lower 16-bits * swap most significant two bytes with 16-bit rotate * * Some CPUs have special instructions which swap a 32-bit quantity in * a single instruction (e.g. i486). It is probably best to avoid * an "endian swapping control bit" in the CPU. One good reason is * that interrupts would probably have to be disabled to insure that * an interrupt does not try to access the same "chunk" with the wrong * endian. Another good reason is that on some CPUs, the endian bit * endianness for ALL fetches -- both code and data -- so the code * will be fetched incorrectly. * * NO_CPU Specific Information: * * XXX document implementation including references if appropriate */ static inline unsigned int CPU_swap_u32( unsigned int value ) { unsigned32 byte1, byte2, byte3, byte4, swapped; byte4 = (value >> 24) & 0xff; byte3 = (value >> 16) & 0xff; byte2 = (value >> 8) & 0xff; byte1 = value & 0xff; swapped = (byte1 << 24) | (byte2 << 16) | (byte3 << 8) | byte4; return( swapped ); } #define CPU_swap_u16( value ) \ (((value&0xff) << 8) | ((value >> 8)&0xff)) #ifdef __cplusplus } #endif #endif