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Diffstat (limited to 'cpukit/score/cpu/no_cpu/cpu_asm.c')
| -rw-r--r-- | cpukit/score/cpu/no_cpu/cpu_asm.c | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/cpukit/score/cpu/no_cpu/cpu_asm.c b/cpukit/score/cpu/no_cpu/cpu_asm.c new file mode 100644 index 0000000000..26246a93c2 --- /dev/null +++ b/cpukit/score/cpu/no_cpu/cpu_asm.c @@ -0,0 +1,152 @@ +/* cpu_asm.c ===> cpu_asm.S or cpu_asm.s + * + * This file contains the basic algorithms for all assembly code used + * in an specific CPU port of RTEMS. These algorithms must be implemented + * in assembly language + * + * NOTE: This is supposed to be a .S or .s file NOT a C file. + * + * COPYRIGHT (c) 1989, 1990, 1991, 1992, 1993, 1994. + * On-Line Applications Research Corporation (OAR). + * All rights assigned to U.S. Government, 1994. + * + * This material may be reproduced by or for the U.S. Government pursuant + * to the copyright license under the clause at DFARS 252.227-7013. This + * notice must appear in all copies of this file and its derivatives. + * + * $Id$ + */ + +/* + * This is supposed to be an assembly file. This means that system.h + * and cpu.h should not be included in a "real" cpu_asm file. An + * implementation in assembly should include "cpu_asm.h> + */ + +#include <rtems/system.h> +#include <rtems/cpu.h> +/* #include "cpu_asm.h> */ + +/* + * _CPU_Context_save_fp_context + * + * This routine is responsible for saving the FP context + * at *fp_context_ptr. If the point to load the FP context + * from is changed then the pointer is modified by this routine. + * + * Sometimes a macro implementation of this is in cpu.h which dereferences + * the ** and a similarly named routine in this file is passed something + * like a (Context_Control_fp *). The general rule on making this decision + * is to avoid writing assembly language. + */ + +void _CPU_Context_save_fp( + void **fp_context_ptr +) +{ +} + +/* + * _CPU_Context_restore_fp_context + * + * This routine is responsible for restoring the FP context + * at *fp_context_ptr. If the point to load the FP context + * from is changed then the pointer is modified by this routine. + * + * Sometimes a macro implementation of this is in cpu.h which dereferences + * the ** and a similarly named routine in this file is passed something + * like a (Context_Control_fp *). The general rule on making this decision + * is to avoid writing assembly language. + */ + +void _CPU_Context_restore_fp( + void **fp_context_ptr +) +{ +} + +/* _CPU_Context_switch + * + * This routine performs a normal non-FP context switch. + */ + +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 +) +{ +} + +/* void __ISR_Handler() + * + * This routine provides the RTEMS interrupt management. + * + */ + +void _ISR_Handler() +{ + /* + * This discussion ignores a lot of the ugly details in a real + * implementation such as saving enough registers/state to be + * able to do something real. Keep in mind that the goal is + * to invoke a user's ISR handler which is written in C and + * uses a certain set of registers. + * + * Also note that the exact order is to a large extent flexible. + * Hardware will dictate a sequence for a certain subset of + * _ISR_Handler while requirements for setting + */ + + /* + * At entry to "common" _ISR_Handler, the vector number must be + * available. On some CPUs the hardware puts either the vector + * number or the offset into the vector table for this ISR in a + * known place. If the hardware does not give us this information, + * then the assembly portion of RTEMS for this port will contain + * a set of distinct interrupt entry points which somehow place + * the vector number in a known place (which is safe if another + * interrupt nests this one) and branches to _ISR_Handler. + * + * save some or all context on stack + * may need to save some special interrupt information for exit + * + * #if ( CPU_HAS_SOFTWARE_INTERRUPT_STACK == TRUE ) + * if ( _ISR_Nest_level == 0 ) + * switch to software interrupt stack + * #endif + * + * _ISR_Nest_level++; + * + * _Thread_Dispatch_disable_level++; + * + * (*_ISR_Vector_table[ vector ])( vector ); + * + * if ( --__ISR_Nest_level == 0 ) { + * if ( _Context_Switch_necessary || _ISR_Signals_to_thread_executing ) + * call _Thread_Dispatch() or prepare to return to _ISR_Dispatch + * #if ( CPU_HAS_SOFTWARE_INTERRUPT_STACK == TRUE ) + * restore stack + * #endif + * } + * + * prepare to get out of interrupt + * return from interrupt + * + */ +} + |