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Diffstat (limited to 'c/src/exec/score/cpu/sparc/cpu.h')
| -rw-r--r-- | c/src/exec/score/cpu/sparc/cpu.h | 986 |
1 files changed, 986 insertions, 0 deletions
diff --git a/c/src/exec/score/cpu/sparc/cpu.h b/c/src/exec/score/cpu/sparc/cpu.h new file mode 100644 index 0000000000..6b9890d132 --- /dev/null +++ b/c/src/exec/score/cpu/sparc/cpu.h @@ -0,0 +1,986 @@ +/* cpu.h + * + * This include file contains information pertaining to the XXX + * processor. + * + * $Id$ + */ + +#ifndef __CPU_h +#define __CPU_h + +#ifdef __cplusplus +extern "C" { +#endif + +#include <rtems/score/sparc.h> /* pick up machine definitions */ +#ifndef ASM +#include <rtems/score/sparctypes.h> +#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 the executive 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.] + */ + +#define CPU_INLINE_ENABLE_DISPATCH TRUE + +/* + * 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 the executive. So it is + * necessary to strike a balance when setting this parameter. + */ + +#define CPU_UNROLL_ENQUEUE_PRIORITY TRUE + +/* + * Does the executive manage a dedicated interrupt stack in software? + * + * If TRUE, then a stack is allocated in _Interrupt_Manager_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 the executive 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. + */ + +#define CPU_HAS_SOFTWARE_INTERRUPT_STACK FALSE /* XXX */ + +/* + * 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. + */ + +#define CPU_HAS_HARDWARE_INTERRUPT_STACK TRUE /* XXX */ + +/* + * Do we 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. + */ + +#define CPU_ALLOCATE_INTERRUPT_STACK TRUE + +/* + * Does the CPU have hardware floating point? + * + * If TRUE, then the FLOATING_POINT task attribute is supported. + * If FALSE, then the 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 "SPARC_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. + */ + +#if ( SPARC_HAS_FPU == 1 ) +#define CPU_HARDWARE_FP TRUE +#else +#define CPU_HARDWARE_FP FALSE +#endif + +/* + * Are all tasks FLOATING_POINT tasks implicitly? + * + * If TRUE, then the FLOATING_POINT task attribute is assumed. + * If FALSE, then the FLOATING_POINT task attribute is followed. + * + * So far, the only CPU in which this option has been used is the + * HP PA-RISC. The HP C compiler and gcc both implicitly use the + * floating point registers to perform integer multiplies. 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. + */ + +#define CPU_ALL_TASKS_ARE_FP FALSE + +/* + * Should the IDLE task have a floating point context? + * + * If TRUE, then the IDLE task is created as a 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. + */ + +#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. + */ + +#define CPU_USE_DEFERRED_FP_SWITCH TRUE + +/* + * Does this port provide a CPU dependent IDLE task implementation? + * + * If TRUE, then the routine _CPU_Internal_threads_Idle_thread_body + * must be provided and is the default IDLE thread body instead of + * _Internal_threads_Idle_thread_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) + */ + +#define CPU_PROVIDES_IDLE_THREAD_BODY FALSE + +/* + * 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. + */ + +#define CPU_STACK_GROWS_UP FALSE + +/* + * The following is the variable attribute used to force alignment + * of critical data 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. + */ + +#define CPU_STRUCTURE_ALIGNMENT __attribute__ ((aligned (16))) + +/* + * 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(). + */ + +#define CPU_MODES_INTERRUPT_MASK 0x0000000F + +/* + * Processor defined structures + * + * Examples structures include the descriptor tables from the i386 + * and the processor control structure on the i960ca. + */ + +/* XXX 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 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 context switches, it is probably not + * enough for a debugger such as gdb. But that is another problem. + */ + +#ifndef ASM + +/* XXX */ +typedef struct { + unsigned32 g0; + unsigned32 g1; + unsigned32 g2; + unsigned32 g3; + unsigned32 g4; + unsigned32 g5; + unsigned32 g6; + unsigned32 g7; + + unsigned32 l0; + unsigned32 l1; + unsigned32 l2; + unsigned32 l3; + unsigned32 l4; + unsigned32 l5; + unsigned32 l6; + unsigned32 l7; + + unsigned32 i0; + unsigned32 i1; + unsigned32 i2; + unsigned32 i3; + unsigned32 i4; + unsigned32 i5; + unsigned32 i6; + unsigned32 i7; + + unsigned32 o0; + unsigned32 o1; + unsigned32 o2; + unsigned32 o3; + unsigned32 o4; + unsigned32 o5; + unsigned32 o6; + unsigned32 o7; + + unsigned32 wim; + unsigned32 psr; +} Context_Control; + +#endif /* ASM */ + +/* + * Offsets of fields with Context_Control for assembly routines. + */ + +#define G0_OFFSET 0x00 +#define G1_OFFSET 0x04 +#define G2_OFFSET 0x08 +#define G3_OFFSET 0x0C +#define G4_OFFSET 0x10 +#define G5_OFFSET 0x14 +#define G6_OFFSET 0x18 +#define G7_OFFSET 0x1C + +#define L0_OFFSET 0x20 +#define L1_OFFSET 0x24 +#define L2_OFFSET 0x28 +#define L3_OFFSET 0x2C +#define L4_OFFSET 0x30 +#define L5_OFFSET 0x34 +#define L6_OFFSET 0x38 +#define L7_OFFSET 0x3C + +#define I0_OFFSET 0x40 +#define I1_OFFSET 0x44 +#define I2_OFFSET 0x48 +#define I3_OFFSET 0x4C +#define I4_OFFSET 0x50 +#define I5_OFFSET 0x54 +#define I6_OFFSET 0x58 +#define I7_OFFSET 0x5C + +#define O0_OFFSET 0x60 +#define O1_OFFSET 0x64 +#define O2_OFFSET 0x68 +#define O3_OFFSET 0x6C +#define O4_OFFSET 0x70 +#define O5_OFFSET 0x74 +#define O6_OFFSET 0x78 +#define O7_OFFSET 0x7C + +#define WIM_OFFSET 0x80 +#define PSR_OFFSET 0x84 + +#ifndef ASM + +/* XXX */ +typedef struct { + double f0_f1; + double f2_f3; + double f4_f5; + double f6_f7; + double f8_f9; + double f10_f11; + double f12_f13; + double f14_f15; + double f16_f17; + double f18_f19; + double f20_f21; + double f22_f23; + double f24_f25; + double f26_f27; + double f28_f29; + double f30_f31; + unsigned32 fsr; +} Context_Control_fp; + +#endif /* ASM */ + +/* + * Offsets of fields with Context_Control_fp for assembly routines. + */ + +#define FO_F1_OFFSET 0x00 +#define F2_F3_OFFSET 0x08 +#define F4_F5_OFFSET 0x10 +#define F6_F7_OFFSET 0x18 +#define F8_F9_OFFSET 0x20 +#define F1O_F11_OFFSET 0x28 +#define F12_F13_OFFSET 0x30 +#define F14_F15_OFFSET 0x38 +#define F16_F17_OFFSET 0x40 +#define F18_F19_OFFSET 0x48 +#define F2O_F21_OFFSET 0x50 +#define F22_F23_OFFSET 0x58 +#define F24_F25_OFFSET 0x60 +#define F26_F27_OFFSET 0x68 +#define F28_F29_OFFSET 0x70 +#define F3O_F31_OFFSET 0x78 +#define FSR_OFFSET 0x80 + +#ifndef ASM + +typedef struct { + unsigned32 special_interrupt_register_XXX; +} CPU_Interrupt_frame; + +#endif /* ASM */ + +/* + * Offsets of fields with CPU_Interrupt_frame for assembly routines. + */ + +#ifndef ASM + +/* + * The following table contains the information required to configure + * the XXX processor specific parameters. + * + * NOTE: The interrupt_stack_size field is required if + * CPU_ALLOCATE_INTERRUPT_STACK is defined as TRUE. + * + * The pretasking_hook, predriver_hook, and postdriver_hook, + * and the do_zero_of_workspace fields are required on ALL CPUs. + */ + +typedef struct { + void (*pretasking_hook)( void ); + void (*predriver_hook)( void ); + void (*postdriver_hook)( void ); + void (*idle_task)( void ); + boolean do_zero_of_workspace; + unsigned32 interrupt_stack_size; + unsigned32 extra_system_initialization_stack; + unsigned32 some_other_cpu_dependent_info_XXX; +} rtems_cpu_table; + +/* + * 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. + */ + +EXTERN Context_Control_fp _CPU_Null_fp_context CPU_STRUCTURE_ALIGNMENT; + +/* + * On some CPUs, software managed interrupt stack is supported. + * 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. + */ + +EXTERN void *_CPU_Interrupt_stack_low; +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). + */ + +EXTERN void (*_CPU_Thread_dispatch_pointer)(); + +/* + * Nothing prevents the porter from declaring more CPU specific variables. + */ + +/* 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. + */ + +#define CPU_CONTEXT_FP_SIZE sizeof( Context_Control_fp ) + +/* + * Amount of extra stack (above minimum stack size) required by + * system initialization thread. Remember that in a multiprocessor + * system the system intialization thread becomes the MP server thread. + */ + +#define CPU_SYSTEM_INITIALIZATION_THREAD_EXTRA_STACK 1024 + +/* + * This defines the number of entries in the ISR_Vector_table managed + * by the executive. + */ + +#define CPU_INTERRUPT_NUMBER_OF_VECTORS 255 + +/* + * Should be large enough to run all tests. This insures + * that a "reasonable" small application should not have any problems. + */ + +#define CPU_STACK_MINIMUM_SIZE (1024*2) + +/* + * CPU's worst alignment requirement for data types on a byte boundary. This + * alignment does not take into account the requirements for the stack. + */ + +#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. It does have to + * be greater or equal to than CPU_ALIGNMENT. + */ + +#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. + */ + +#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. + */ + +#define CPU_STACK_ALIGNMENT 16 + +#endif /* ASM */ + +#ifndef ASM + +/* ISR handler macros */ + +/* + * Disable all interrupts for a critical section. The previous + * level is returned in _level. + */ + +#define _CPU_ISR_Disable( _level ) \ + sparc_disable_interrupts( _level ) + +/* + * Enable interrupts to the previous level (returned by _CPU_ISR_Disable). + * This indicates the end of a critical section. The parameter + * _level is not modified. + */ + +#define _CPU_ISR_Enable( _level ) \ + sparc_enable_interrupts( _level ) + +/* + * This temporarily restores the interrupt to _level before immediately + * disabling them again. This is used to divide long critical + * sections into two or more parts. The parameter _level is not + * modified. + */ + +#define _CPU_ISR_Flash( _level ) \ + sparc_flash_interrupts( _level ) + +/* + * 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. + */ + +#define _CPU_ISR_Set_level( _newlevel ) \ + sparc_set_interrupt_level( _newlevel ) + +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: Implemented as a subroutine for the SPARC port. + */ + +void _CPU_Context_Initialize( + Context_Control *_the_context, + unsigned32 *_stack_base, + unsigned32 _size, + unsigned32 _new_level, + void *_entry_point +); + +/* + * 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. + */ + +#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. + */ + +#define _CPU_Context_Fp_start( _base, _offset ) \ + ( (void *) (_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. + */ + +#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. + */ + +#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. + * + * The executive 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 + */ + +#ifndef INIT + extern const unsigned char __log2table[256]; +#else +const unsigned char __log2table[256] = { + 0, 0, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, + 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, + 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, + 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, + 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, + 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, + 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, + 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, + 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, + 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, + 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, + 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, + 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, + 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, + 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, + 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7 +}; +#endif + +#define _CPU_Bitfield_Find_first_bit( _value, _output ) \ + { \ + register __value = (_value); \ + \ + if ( !(__value & 0xff00) ) \ + (_output) = __log2table[ __value ]; \ + else \ + (_output) = __log2table[ __value >> 8 ] + 8; \ + } + + +/* 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. + */ + +#define _CPU_Priority_Mask( _bit_number ) \ + ( 0x8000 >> (_bit_number) ) + +/* + * 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. + */ + +#define _CPU_Priority_Bits_index( _priority ) \ + (15 - (_priority)) + +/* end of Priority handler macros */ + +/* functions */ + +/* + * _CPU_Initialize + * + * This routine performs CPU dependent initialization. + */ + +void _CPU_Initialize( + rtems_cpu_table *cpu_table, + void (*thread_dispatch) +); + +/* + * _CPU_ISR_install_vector + * + * This routine installs an interrupt vector. + */ + +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. + */ + +void _CPU_Install_interrupt_stack( void ); + +/* + * _CPU_Internal_threads_Idle_thread_body + * + * This routine is the CPU dependent IDLE thread body. + * + * NOTE: It need only be provided if CPU_PROVIDES_IDLE_THREAD_BODY + * is TRUE. + */ + +void _CPU_Internal_threads_Idle_thread_body( void ); + +/* + * _CPU_Context_switch + * + * This routine switches from the run context to the heir context. + */ + +void _CPU_Context_switch( + Context_Control *run, + Context_Control *heir +); + +/* + * _CPU_Context_restore + * + * This routine is generallu 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. + */ + +void _CPU_Context_restore( + Context_Control *new_context +); + +/* + * _CPU_Context_save_fp + * + * This routine saves the floating point context passed to it. + */ + +void _CPU_Context_save_fp( + void **fp_context_ptr +); + +/* + * _CPU_Context_restore_fp + * + * This routine restores the floating point context passed to it. + */ + +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. + */ + +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 ); +} + +#endif ASM + +#ifdef __cplusplus +} +#endif + +#endif |