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view src/nucleus/pic.c @ 19:399779c700da
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| author | Mychaela Falconia <falcon@freecalypso.org> |
|---|---|
| date | Fri, 15 May 2020 05:59:55 +0000 |
| parents | 92470e5d0b9e |
| children |
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/*************************************************************************/ /* */ /* Copyright Mentor Graphics Corporation 2002 */ /* All Rights Reserved. */ /* */ /* THIS WORK CONTAINS TRADE SECRET AND PROPRIETARY INFORMATION WHICH IS */ /* THE PROPERTY OF MENTOR GRAPHICS CORPORATION OR ITS LICENSORS AND IS */ /* SUBJECT TO LICENSE TERMS. */ /* */ /*************************************************************************/ /*************************************************************************/ /* */ /* FILE NAME VERSION */ /* */ /* pic.c Nucleus PLUS 1.14 */ /* */ /* COMPONENT */ /* */ /* PI - Pipe Management */ /* */ /* DESCRIPTION */ /* */ /* This file contains the core routines for the pipe management */ /* component. */ /* */ /* DATA STRUCTURES */ /* */ /* None */ /* */ /* FUNCTIONS */ /* */ /* PIC_Create_Pipe Create a message pipe */ /* PIC_Delete_Pipe Delete a message pipe */ /* PIC_Send_To_Pipe Send message to a pipe */ /* PIC_Receive_From_Pipe Receive a message from pipe */ /* PIC_Cleanup Cleanup on timeout or a */ /* terminate condition */ /* */ /* DEPENDENCIES */ /* */ /* cs_extr.h Common Service functions */ /* tc_extr.h Thread Control functions */ /* pi_extr.h Pipe functions */ /* hi_extr.h History functions */ /* */ /* HISTORY */ /* */ /* DATE REMARKS */ /* */ /* 03-01-1993 Created initial version 1.0 */ /* 04-19-1993 Verified version 1.0 */ /* 08-09-1993 Corrected pointer retrieval */ /* loop, resulting in version 1.0a */ /* 08-09-1993 Verified version 1.0a */ /* 03-01-1994 Moved non-core functions into */ /* supplemental files, changed */ /* function interfaces to match */ /* those in prototype, added */ /* register options, changed */ /* protection logic to reduce */ /* overhead, corrected bug in */ /* pipe reset, optimized item */ /* copy loops, resulting in */ /* version 1.1 */ /* */ /* 03-18-1994 Verified version 1.1 */ /* 04-17-1996 updated to version 1.2 */ /* 03-24-1998 Released version 1.3 */ /* 03-26-1999 Released 1.11m (new release */ /* numbering scheme) */ /* 04-17-2002 Released version 1.13m */ /* 11-07-2002 Released version 1.14 */ /*************************************************************************/ #define NU_SOURCE_FILE #include "cs_extr.h" /* Common service functions */ #include "tc_extr.h" /* Thread control functions */ #include "pi_extr.h" /* Pipe functions */ #include "hi_extr.h" /* History functions */ #include "profiler.h" /* ProView interface */ /* Define external inner-component global data references. */ extern CS_NODE *PID_Created_Pipes_List; extern UNSIGNED PID_Total_Pipes; extern TC_PROTECT PID_List_Protect; /* Define internal component function prototypes. */ VOID PIC_Cleanup(VOID *information); /*************************************************************************/ /* */ /* FUNCTION */ /* */ /* PIC_Create_Pipe */ /* */ /* DESCRIPTION */ /* */ /* This function creates a pipe and then places it on the list */ /* of created pipes. */ /* */ /* CALLED BY */ /* */ /* Application */ /* PICE_Create_Pipe Error checking shell */ /* */ /* CALLS */ /* */ /* CSC_Place_On_List Add to node to linked-list */ /* [HIC_Make_History_Entry] Make entry in history log */ /* [TCT_Check_Stack] Stack checking function */ /* TCT_Protect Data structure protect */ /* TCT_Unprotect Un-protect data structure */ /* */ /* INPUTS */ /* */ /* pipe_ptr Pipe control block pointer */ /* name Pipe name */ /* start_address Starting address of actual */ /* pipe area */ /* pipe_size Total size of pipe in bytes */ /* message_type Type of message supported by */ /* the pipe (fixed/variable) */ /* message_size Size of message. Variable */ /* message-length pipes, this */ /* represents the maximum size*/ /* suspend_type Suspension type */ /* */ /* OUTPUTS */ /* */ /* NU_SUCCESS */ /* */ /* HISTORY */ /* */ /* DATE REMARKS */ /* */ /* 03-01-1993 Created initial version 1.0 */ /* 04-19-1993 Verified version 1.0 */ /* 03-01-1994 Changed function interfaces to */ /* match those in prototype, */ /* added register options, */ /* resulting in version 1.1 */ /* */ /* 03-18-1994 Verified version 1.1 */ /* */ /*************************************************************************/ STATUS PIC_Create_Pipe(NU_PIPE *pipe_ptr, CHAR *name, VOID *start_address, UNSIGNED pipe_size, OPTION message_type, UNSIGNED message_size, OPTION suspend_type) { R1 PI_PCB *pipe; /* Pipe control block ptr */ INT i; /* Working index variable */ NU_SUPERV_USER_VARIABLES /* Switch to supervisor mode */ NU_SUPERVISOR_MODE(); /* Move input pipe pointer into internal pointer. */ pipe = (PI_PCB *) pipe_ptr; #ifdef NU_ENABLE_STACK_CHECK /* Call stack checking function to check for an overflow condition. */ TCT_Check_Stack(); #endif #ifdef NU_ENABLE_HISTORY /* Make an entry that corresponds to this function in the system history log. */ HIC_Make_History_Entry(NU_CREATE_PIPE_ID, (UNSIGNED) pipe, (UNSIGNED) name, (UNSIGNED) start_address); #endif /* First, clear the pipe ID just in case it is an old pipe Control Block. */ pipe -> pi_id = 0; /* Fill in the pipe name. */ for (i = 0; i < NU_MAX_NAME; i++) pipe -> pi_name[i] = name[i]; /* Setup the pipe suspension type. */ if (suspend_type == NU_FIFO) /* FIFO suspension is selected, setup the flag accordingly. */ pipe -> pi_fifo_suspend = NU_TRUE; else /* Priority suspension is selected. */ pipe -> pi_fifo_suspend = NU_FALSE; /* Setup the pipe message type. */ if (message_type == NU_FIXED_SIZE) /* Fixed-size messages are required. */ pipe -> pi_fixed_size = NU_TRUE; else /* Variable-size messages are required. */ pipe -> pi_fixed_size = NU_FALSE; /* Setup the message size. */ pipe -> pi_message_size = message_size; /* Clear the messages counter. */ pipe -> pi_messages = 0; /* Setup the actual pipe pointers. */ pipe -> pi_pipe_size = pipe_size; /* Determine if the pipe's size needs to be adjusted. */ if (pipe -> pi_fixed_size) /* The size of a fixed-size message pipe must be an even multiple of the actual message size. */ pipe_size = (pipe_size/message_size) * message_size; else /* Insure that the size is in terms of UNSIGNED data elements. This insures that the UNSIGNED word is never written past the end of the pipe. */ pipe_size = (pipe_size/sizeof(UNSIGNED)) * sizeof(UNSIGNED); pipe -> pi_available = pipe_size; pipe -> pi_start = (BYTE_PTR) start_address; pipe -> pi_end = pipe -> pi_start + pipe_size; pipe -> pi_read = (BYTE_PTR) start_address; pipe -> pi_write = (BYTE_PTR) start_address; /* Clear the suspension list pointer. */ pipe -> pi_suspension_list = NU_NULL; /* Clear the number of tasks waiting on the pipe counter. */ pipe -> pi_tasks_waiting = 0; /* Clear the urgent message list pointer. */ pipe -> pi_urgent_list = NU_NULL; /* Initialize link pointers. */ pipe -> pi_created.cs_previous = NU_NULL; pipe -> pi_created.cs_next = NU_NULL; /* Protect against access to the list of created pipes. */ TCT_Protect(&PID_List_Protect); /* At this point the pipe is completely built. The ID can now be set and it can be linked into the created pipe list. */ pipe -> pi_id = PI_PIPE_ID; /* Link the pipe into the list of created pipes and increment the total number of pipes in the system. */ CSC_Place_On_List(&PID_Created_Pipes_List, &(pipe -> pi_created)); PID_Total_Pipes++; #ifdef INCLUDE_PROVIEW _RTProf_DumpPipe(RT_PROF_CREATE_PIPE,pipe,RT_PROF_OK); #endif /* INCLUDE_PROVIEW */ /* Release protection against access to the list of created pipes. */ TCT_Unprotect(); /* Return to user mode */ NU_USER_MODE(); /* Return successful completion. */ return(NU_SUCCESS); } /*************************************************************************/ /* */ /* FUNCTION */ /* */ /* PIC_Delete_Pipe */ /* */ /* DESCRIPTION */ /* */ /* This function deletes a pipe and removes it from the list of */ /* created pipes. All tasks suspended on the pipe are */ /* resumed. Note that this function does not free the memory */ /* associated with the pipe. */ /* */ /* CALLED BY */ /* */ /* Application */ /* PICE_Delete_Pipe Error checking shell */ /* */ /* CALLS */ /* */ /* CSC_Remove_From_List Remove node from list */ /* [HIC_Make_History_Entry] Make entry in history log */ /* TCC_Resume_Task Resume a suspended task */ /* [TCT_Check_Stack] Stack checking function */ /* TCT_Control_To_System Transfer control to system */ /* TCT_Protect Protect created list */ /* TCT_Set_Current_Protect Modify current protection */ /* TCT_System_Protect Protect against system access*/ /* TCT_System_Unprotect Release system protection */ /* TCT_Unprotect Release protection */ /* */ /* INPUTS */ /* */ /* pipe_ptr Pipe control block pointer */ /* */ /* OUTPUTS */ /* */ /* NU_SUCCESS */ /* */ /* HISTORY */ /* */ /* DATE REMARKS */ /* */ /* 03-01-1993 Created initial version 1.0 */ /* 04-19-1993 Verified version 1.0 */ /* 03-01-1994 Changed function interfaces to */ /* match those in prototype, */ /* added register options, changed */ /* protection logic to reduce */ /* overhead, resulting in */ /* version 1.1 */ /* */ /* 03-18-1994 Verified version 1.1 */ /* */ /*************************************************************************/ STATUS PIC_Delete_Pipe(NU_PIPE *pipe_ptr) { R1 PI_PCB *pipe; /* Pipe control block ptr */ PI_SUSPEND *suspend_ptr; /* Suspend block pointer */ PI_SUSPEND *next_ptr; /* Next suspension block ptr */ STATUS preempt; /* Status for resume call */ NU_SUPERV_USER_VARIABLES /* Switch to supervisor mode */ NU_SUPERVISOR_MODE(); /* Move input pipe pointer into internal pointer. */ pipe = (PI_PCB *) pipe_ptr; #ifdef NU_ENABLE_STACK_CHECK /* Call stack checking function to check for an overflow condition. */ TCT_Check_Stack(); #endif #ifdef NU_ENABLE_HISTORY /* Make an entry that corresponds to this function in the system history log. */ HIC_Make_History_Entry(NU_DELETE_PIPE_ID, (UNSIGNED) pipe, (UNSIGNED) 0, (UNSIGNED) 0); #endif /* Protect against access to the pipe. */ TCT_System_Protect(); #ifdef INCLUDE_PROVIEW _RTProf_DumpPipe(RT_PROF_DELETE_PIPE,pipe,RT_PROF_OK); #endif /* INCLUDE_PROVIEW */ /* Clear the pipe ID. */ pipe -> pi_id = 0; /* Release protection. */ TCT_Unprotect(); /* Protect against access to the list of created pipes. */ TCT_Protect(&PID_List_Protect); /* Remove the pipe from the list of created pipes. */ CSC_Remove_From_List(&PID_Created_Pipes_List, &(pipe -> pi_created)); /* Decrement the total number of created pipes. */ PID_Total_Pipes--; /* Pickup the suspended task pointer list. */ suspend_ptr = pipe -> pi_suspension_list; /* Walk the chain task(s) currently suspended on the pipe. */ preempt = 0; while (suspend_ptr) { /* Protect against system access. */ TCT_System_Protect(); /* Resume the suspended task. Insure that the status returned is NU_PIPE_DELETED. */ suspend_ptr -> pi_return_status = NU_PIPE_DELETED; /* Point to the next suspend structure in the link. */ next_ptr = (PI_SUSPEND *) (suspend_ptr -> pi_suspend_link.cs_next); /* Resume the specified task. */ preempt = preempt | TCC_Resume_Task((NU_TASK *) suspend_ptr -> pi_suspended_task, NU_PIPE_SUSPEND); /* Determine if the next is the same as the head pointer. */ if (next_ptr == pipe -> pi_suspension_list) /* Clear the suspension pointer to signal the end of the list traversal. */ suspend_ptr = NU_NULL; else /* Setup the next suspension pointer. */ suspend_ptr = next_ptr; /* Modify current protection. */ TCT_Set_Current_Protect(&PID_List_Protect); /* Clear the system protection. */ TCT_System_Unprotect(); } /* Pickup the urgent message suspension list. */ suspend_ptr = pipe -> pi_urgent_list; /* Walk the chain task(s) currently suspended on the pipe. */ while (suspend_ptr) { /* Protect against system access. */ TCT_System_Protect(); /* Resume the suspended task. Insure that the status returned is NU_PIPE_DELETED. */ suspend_ptr -> pi_return_status = NU_PIPE_DELETED; /* Point to the next suspend structure in the link. */ next_ptr = (PI_SUSPEND *) (suspend_ptr -> pi_suspend_link.cs_next); /* Resume the specified task. */ preempt = preempt | TCC_Resume_Task((NU_TASK *) suspend_ptr -> pi_suspended_task, NU_PIPE_SUSPEND); /* Determine if the next is the same as the head pointer. */ if (next_ptr == pipe -> pi_urgent_list) /* Clear the suspension pointer to signal the end of the list traversal. */ suspend_ptr = NU_NULL; else /* Position suspend pointer to the next block. */ suspend_ptr = next_ptr; /* Modify current protection. */ TCT_Set_Current_Protect(&PID_List_Protect); /* Clear the system protection. */ TCT_System_Unprotect(); } /* Determine if preemption needs to occur. */ if (preempt) /* Transfer control to system to facilitate preemption. */ TCT_Control_To_System(); /* Release protection against access to the list of created pipes. */ TCT_Unprotect(); /* Return to user mode */ NU_USER_MODE(); /* Return a successful completion. */ return(NU_SUCCESS); } /*************************************************************************/ /* */ /* FUNCTION */ /* */ /* PIC_Send_To_Pipe */ /* */ /* DESCRIPTION */ /* */ /* This function sends a message to the specified pipe. The */ /* message length is determined by the caller. If there are one */ /* or more tasks suspended on the pipe for a message, the message */ /* is copied into the message area of the first waiting task. If */ /* the task's request is satisfied, it is resumed. Otherwise, if */ /* the pipe cannot hold the message, suspension of the calling */ /* task is an option of the caller. */ /* */ /* CALLED BY */ /* */ /* Application */ /* PICE_Send_To_Pipe Error checking shell */ /* */ /* CALLS */ /* */ /* CSC_Place_On_List Place on suspend list */ /* CSC_Priority_Place_On_List Place on priority list */ /* CSC_Remove_From_List Remove from suspend list */ /* [HIC_Make_History_Entry] Make entry in history log */ /* TCC_Resume_Task Resume a suspended task */ /* TCC_Suspend_Task Suspend calling task */ /* TCC_Task_Priority Pickup task's priority */ /* [TCT_Check_Stack] Stack checking function */ /* TCT_Control_To_System Transfer control to system */ /* TCT_Current_Thread Pickup current thread pointer*/ /* TCT_System_Protect Protect pipe */ /* TCT_Unprotect Release protection */ /* */ /* INPUTS */ /* */ /* pipe_ptr Pipe control block pointer */ /* message Pointer to message to send */ /* size Size of message to send */ /* suspend Suspension option if full */ /* */ /* OUTPUTS */ /* */ /* NU_SUCCESS If service is successful */ /* NU_PIPE_FULL If pipe is currently full */ /* NU_TIMEOUT If timeout on service expires*/ /* NU_PIPE_DELETED If pipe was deleted during */ /* suspension */ /* NU_PIPE_RESET If pipe was reset during */ /* suspension */ /* */ /* HISTORY */ /* */ /* DATE REMARKS */ /* */ /* 03-01-1993 Created initial version 1.0 */ /* 04-19-1993 Verified version 1.0 */ /* 03-01-1994 Changed function interfaces to */ /* match those in prototype, */ /* added register options, changed */ /* protection logic to reduce */ /* overhead, optimized copy loop, */ /* resulting in version 1.1 */ /* */ /* 03-18-1994 Verified version 1.1 */ /* */ /*************************************************************************/ STATUS PIC_Send_To_Pipe(NU_PIPE *pipe_ptr, VOID *message, UNSIGNED size, UNSIGNED suspend) { R1 PI_PCB *pipe; /* Pipe control block ptr */ PI_SUSPEND suspend_block; /* Allocate suspension block */ PI_SUSPEND *suspend_ptr; /* Pointer to suspend block */ R2 BYTE_PTR source; /* Pointer to source */ R3 BYTE_PTR destination; /* Pointer to destination */ UNSIGNED copy_size; /* Partial copy size */ R4 INT i; /* Working counter */ UNSIGNED pad = 0; /* Number of pad bytes */ TC_TCB *task; /* Task pointer */ STATUS preempt; /* Preempt flag */ STATUS status; /* Completion status */ NU_SUPERV_USER_VARIABLES /* Switch to supervisor mode */ NU_SUPERVISOR_MODE(); /* Move input pipe pointer into internal pointer. */ pipe = (PI_PCB *) pipe_ptr; #ifdef NU_ENABLE_STACK_CHECK /* Call stack checking function to check for an overflow condition. */ TCT_Check_Stack(); #endif #ifdef NU_ENABLE_HISTORY /* Make an entry that corresponds to this function in the system history log. */ HIC_Make_History_Entry(NU_SEND_TO_PIPE_ID, (UNSIGNED) pipe, (UNSIGNED) message, (UNSIGNED) size); #endif /* Initialize the status as successful. */ status = NU_SUCCESS; /* Protect against simultaneous access to the pipe. */ TCT_System_Protect(); /* Determine if an extra word of overhead needs to be added to the calculation. */ if (pipe -> pi_fixed_size) /* No overhead. */ i = 0; else { /* Variable messages have one additional word of overhead. */ i = sizeof(UNSIGNED); /* Calculate the number of pad bytes necessary to make keep the pipe write pointer on an UNSIGNED data element alignment. */ pad = (((size + sizeof(UNSIGNED) - 1)/sizeof(UNSIGNED)) * sizeof(UNSIGNED)) - size; /* Insure that padding is included in the overhead. */ i = i + ((INT) pad); /* Make special check to see if a suspension needs to be forced for a variable length message. */ if ((pipe -> pi_suspension_list) && (pipe -> pi_messages)) { /* Pickup task control block pointer. */ task = (TC_TCB *) TCT_Current_Thread(); /* Now we know that there are other task(s) are suspended trying to send a variable length message. Determine whether or not a suspension should be forced. */ if ((pipe -> pi_fifo_suspend) || (suspend == NU_NO_SUSPEND) || ((pipe -> pi_suspension_list) -> pi_suspend_link.cs_priority <= TCC_Task_Priority(task))) /* Bump the computed size to avoid placing the new variable length message ahead of the suspended tasks. */ i = (INT) pipe -> pi_available; } } /* Determine if there is enough room in the pipe for the message. */ if (pipe -> pi_available < (size + i)) { /* pipe does not have room for the message. Determine if suspension is required. */ if (suspend) { /* Suspension is requested. */ /* Increment the number of tasks waiting. */ pipe -> pi_tasks_waiting++; #ifdef INCLUDE_PROVIEW _RTProf_DumpPipe(RT_PROF_SEND_TO_PIPE,pipe,RT_PROF_WAIT); #endif /* INCLUDE_PROVIEW */ /* Setup the suspend block and suspend the calling task. */ suspend_ptr = &suspend_block; suspend_ptr -> pi_pipe = pipe; suspend_ptr -> pi_suspend_link.cs_next = NU_NULL; suspend_ptr -> pi_suspend_link.cs_previous= NU_NULL; suspend_ptr -> pi_message_area = (BYTE_PTR) message; suspend_ptr -> pi_message_size = size; task = (TC_TCB *) TCT_Current_Thread(); suspend_ptr -> pi_suspended_task = task; /* Determine if priority or FIFO suspension is associated with the pipe. */ if (pipe -> pi_fifo_suspend) { /* FIFO suspension is required. Link the suspend block into the list of suspended tasks on this pipe. */ CSC_Place_On_List((CS_NODE **) &(pipe -> pi_suspension_list), &(suspend_ptr -> pi_suspend_link)); } else { /* Get the priority of the current thread so the suspend block can be placed in the appropriate place. */ suspend_ptr -> pi_suspend_link.cs_priority = TCC_Task_Priority(task); CSC_Priority_Place_On_List((CS_NODE **) &(pipe -> pi_suspension_list), &(suspend_ptr -> pi_suspend_link)); } /* Finally, suspend the calling task. Note that the suspension call automatically clears the protection on the pipe. */ TCC_Suspend_Task((NU_TASK *) task, NU_PIPE_SUSPEND, PIC_Cleanup, suspend_ptr, suspend); /* Pickup the return status. */ status = suspend_ptr -> pi_return_status; } else { /* Return a status of NU_PIPE_FULL because there is no room in the pipe for the message. */ status = NU_PIPE_FULL; #ifdef INCLUDE_PROVIEW _RTProf_DumpPipe(RT_PROF_SEND_TO_PIPE,pipe,RT_PROF_FAIL); #endif /* INCLUDE_PROVIEW */ } } else { /* Determine if a task is waiting on an empty pipe. */ if ((pipe -> pi_suspension_list) && (pipe -> pi_messages == 0)) { /* Task is waiting on pipe for a message. */ /* Decrement the number of tasks waiting on pipe. */ pipe -> pi_tasks_waiting--; #ifdef INCLUDE_PROVIEW _RTProf_DumpPipe(RT_PROF_SEND_TO_PIPE,pipe,RT_PROF_OK); #endif /* INCLUDE_PROVIEW */ /* Remove the first suspended block from the list. */ suspend_ptr = pipe -> pi_suspension_list; CSC_Remove_From_List((CS_NODE **) &(pipe -> pi_suspension_list), &(suspend_ptr -> pi_suspend_link)); /* Setup the source and destination pointers. */ source = (BYTE_PTR) message; destination = suspend_ptr -> pi_message_area; /* Initialize the return status. */ suspend_ptr -> pi_return_status = NU_SUCCESS; /* Loop to actually copy the message. */ i = (INT) size; do { *(destination++) = *(source); if ((--i) == 0) break; source++; } while(1); /* Return the size of the message copied. */ suspend_ptr -> pi_actual_size = size; /* Wakeup the waiting task and check for preemption. */ preempt = TCC_Resume_Task((NU_TASK *) suspend_ptr -> pi_suspended_task, NU_PIPE_SUSPEND); /* Determine if preemption needs to take place. */ if (preempt) /* Transfer control to the system if the resumed task function detects a preemption condition. */ TCT_Control_To_System(); } else { /* There is enough room in the pipe and no task is waiting. */ /* Setup the source pointer. */ source = (BYTE_PTR) message; destination = pipe -> pi_write; /* Process according to the type of message supported. */ if (pipe -> pi_fixed_size) { /* Fixed-size messages are supported by this pipe. */ /* Loop to copy the message into the pipe area. */ i = (INT) size; do { *(destination++) = *(source); if ((--i) == 0) break; source++; } while (1); } else { /* Variable-size messages are supported. Processing must check for pipe wrap-around conditions. */ /* Place message size in first location. */ *((UNSIGNED *) destination) = size; destination = destination + sizeof(UNSIGNED); /* Check for a wrap-around condition on the pipe. */ if (destination >= pipe -> pi_end) /* Wrap the write pointer back to the top of the pipe area. */ destination = pipe -> pi_start; /* Decrement the number of bytes remaining for this extra word of overhead. */ pipe -> pi_available = pipe -> pi_available - sizeof(UNSIGNED); /* Calculate the number of bytes remaining from the write pointer to the bottom of the pipe. */ copy_size = pipe -> pi_end - destination; /* Determine if the message needs to be wrapped around the edge of the pipe area. */ if (copy_size >= size) { /* Copy the whole message at once. */ i = (INT) size; do { *(destination++) = *(source); if ((--i) == 0) break; source++; } while (1); } else { /* Copy the first half of the message. */ i = (INT) copy_size; do { *(destination) = *(source++); if ((--i) == 0) break; destination++; } while (1); /* Copy the second half of the message. */ destination = pipe -> pi_start; i = (INT) (size - copy_size); do { *(destination++) = *(source); if ((--i) == 0) break; source++; } while (1); } } /* Check again for wrap-around condition on the write pointer. */ if (destination >= pipe -> pi_end) /* Move the write pointer to the top of the pipe area. */ destination = pipe -> pi_start; /* Determine if the pipe supports variable-length messages. If so, pad bytes are needed to keep UNSIGNED alignment. */ if (pad) { /* Variable-size message. Add pad bytes to the write pointer. */ /* Calculate the number of bytes remaining from the write pointer to the bottom of the pipe. */ copy_size = pipe -> pi_end - destination; /* If there is not enough room at the bottom of the pipe, the pad bytes must be wrapped around to the top. */ if (copy_size <= pad) /* Move write pointer to the top of the pipe and make the necessary adjustment. */ destination = pipe -> pi_start + (pad - copy_size); else /* There is enough room in the pipe to simply add the the pad bytes to the write pointer. */ destination = destination + pad; /* Decrement the number of available bytes. */ pipe -> pi_available = pipe -> pi_available - pad; } /* Update the actual write pointer. */ pipe -> pi_write = destination; /* Decrement the number of available bytes. */ pipe -> pi_available = pipe -> pi_available - size; /* Increment the number of messages in the pipe. */ pipe -> pi_messages++; #ifdef INCLUDE_PROVIEW _RTProf_DumpPipe(RT_PROF_SEND_TO_PIPE,pipe,RT_PROF_OK); #endif /* INCLUDE_PROVIEW */ } } /* Release protection against access to the pipe. */ TCT_Unprotect(); /* Return to user mode */ NU_USER_MODE(); /* Return the completion status. */ return(status); } /*************************************************************************/ /* */ /* FUNCTION */ /* */ /* PIC_Receive_From_Pipe */ /* */ /* DESCRIPTION */ /* */ /* This function receives a message from the specified pipe. The */ /* size of the message is specified by the caller. If there is a */ /* message currently in the pipe, the message is removed from the */ /* pipe and placed in the caller's area. Suspension is possible */ /* if the request cannot be satisfied. */ /* */ /* CALLED BY */ /* */ /* Application */ /* PICE_Receive_From_Pipe Error checking shell */ /* */ /* CALLS */ /* */ /* CSC_Place_On_List Place on suspend list */ /* CSC_Remove_From_List Remove from suspend list */ /* [HIC_Make_History_Entry] Make entry in history log */ /* TCC_Resume_Task Resume a suspended task */ /* TCC_Suspend_Task Suspend calling task */ /* TCC_Task_Priority Pickup task's priority */ /* [TCT_Check_Stack] Stack checking function */ /* TCT_Control_To_System Transfer control to system */ /* TCT_Current_Thread Pickup current thread pointer*/ /* TCT_System_Protect Protect pipe */ /* TCT_Unprotect Release protection */ /* */ /* INPUTS */ /* */ /* pipe_ptr Pipe control block pointer */ /* message Pointer to message to send */ /* size Size of the message */ /* actual_size Size of message received */ /* suspend Suspension option if empty */ /* */ /* OUTPUTS */ /* */ /* NU_SUCCESS If service is successful */ /* NU_PIPE_EMPTY If pipe is currently empty */ /* NU_TIMEOUT If timeout on service expires*/ /* NU_PIPE_DELETED If pipe was deleted during */ /* suspension */ /* NU_PIPE_RESET If pipe was reset during */ /* suspension */ /* */ /* HISTORY */ /* */ /* DATE REMARKS */ /* */ /* 03-01-1993 Created initial version 1.0 */ /* 04-19-1993 Verified version 1.0 */ /* 03-01-1994 Changed function interfaces to */ /* match those in prototype, */ /* added register options, changed */ /* protection logic to reduce */ /* overhead, optimized copy loop, */ /* resulting in version 1.1 */ /* */ /* 03-18-1994 Verified version 1.1 */ /* */ /*************************************************************************/ STATUS PIC_Receive_From_Pipe(NU_PIPE *pipe_ptr, VOID *message, UNSIGNED size, UNSIGNED *actual_size, UNSIGNED suspend) { R1 PI_PCB *pipe; /* Pipe control block ptr */ PI_SUSPEND suspend_block; /* Allocate suspension block */ PI_SUSPEND *suspend_ptr; /* Pointer to suspend block */ R2 BYTE_PTR source; /* Pointer to source */ R3 BYTE_PTR destination; /* Pointer to destination */ TC_TCB *task; /* Task pointer */ UNSIGNED copy_size; /* Number of bytes to copy */ UNSIGNED pad = 0; /* Number of pad bytes */ R4 INT i; /* Working counter */ STATUS preempt; /* Preemption flag */ STATUS status; /* Completion status */ NU_SUPERV_USER_VARIABLES /* Switch to supervisor mode */ NU_SUPERVISOR_MODE(); /* Move input pipe pointer into internal pointer. */ pipe = (PI_PCB *) pipe_ptr; #ifdef NU_ENABLE_STACK_CHECK /* Call stack checking function to check for an overflow condition. */ TCT_Check_Stack(); #endif #ifdef NU_ENABLE_HISTORY /* Make an entry that corresponds to this function in the system history log. */ HIC_Make_History_Entry(NU_RECEIVE_FROM_PIPE_ID, (UNSIGNED) pipe, (UNSIGNED) message, (UNSIGNED) size); #endif /* Initialize the status as successful. */ status = NU_SUCCESS; /* Protect against simultaneous access to the pipe. */ TCT_System_Protect(); /* Determine if an urgent message request is currently suspended. */ if (pipe -> pi_urgent_list) { /* If so, copy the message from the suspended request block and resume the associated task. */ /* Decrement the number of tasks waiting on pipe. */ pipe -> pi_tasks_waiting--; /* Remove the first suspended block from the list. */ suspend_ptr = pipe -> pi_urgent_list; CSC_Remove_From_List((CS_NODE **) &(pipe -> pi_urgent_list), &(suspend_ptr -> pi_suspend_link)); /* Setup the source and destination pointers. */ destination = (BYTE_PTR) message; source = suspend_ptr -> pi_message_area; /* Initialize the return status. */ suspend_ptr -> pi_return_status = NU_SUCCESS; /* Loop to actually copy the message. */ i = (INT) size; do { *(destination++) = *(source); if ((--i) == 0) break; source++; } while (1); /* Return the size of the message copied. */ *actual_size = suspend_ptr -> pi_message_size; /* Wakeup the waiting task and check for preemption. */ preempt = TCC_Resume_Task((NU_TASK *) suspend_ptr -> pi_suspended_task, NU_PIPE_SUSPEND); /* Determine if preemption needs to take place. */ if (preempt) /* Transfer control to the system if the resumed task function detects a preemption condition. */ TCT_Control_To_System(); } /* Determine if there are messages in the pipe. */ else if (pipe -> pi_messages) { /* Copy message from pipe into the caller's area. */ /* Setup the source and destination pointers. */ destination = (BYTE_PTR) message; source = pipe -> pi_read; /* Process according to the type of message supported by the pipe. */ if (pipe -> pi_fixed_size) { /* Pipe supports fixed-size messages. */ /* Copy the message from the pipe area into the destination. */ i = (INT) size; do { *(destination) = *(source++); if ((--i) == 0) break; destination++; } while (1); } else { /* Pipe supports variable-size messages. */ /* Variable length message size is actually in the pipe area. */ size = *((UNSIGNED *) source); source = source + sizeof(UNSIGNED); /* Check for a wrap-around condition on the pipe. */ if (source >= pipe -> pi_end) /* Wrap the read pointer back to the top of the pipe area. */ source = pipe -> pi_start; /* Increment the number of available bytes in the pipe. */ pipe -> pi_available = pipe -> pi_available + sizeof(UNSIGNED); /* Calculate the number of pad bytes necessary to keep the pipe read pointer on an UNSIGNED data element alignment.*/ pad = (((size + sizeof(UNSIGNED) - 1)/sizeof(UNSIGNED)) * sizeof(UNSIGNED)) - size; /* Calculate the number of bytes remaining from the read pointer to the bottom of the pipe. */ copy_size = pipe -> pi_end - source; /* Determine if the message needs to be wrapped around the edge of the pipe area. */ if (copy_size >= size) { /* Copy the whole message at once. */ i = (INT) size; do { *(destination) = *(source++); if ((--i) == 0) break; destination++; } while (1); } else { /* Copy the first half of the message. */ i = (INT) copy_size; do { *(destination++) = *(source); if ((--i) == 0) break; source++; } while (1); /* Copy the second half of the message. */ source = pipe -> pi_start; i = (INT) (size - copy_size); do { *(destination) = *(source++); if ((--i) == 0) break; destination++; } while (1); } } /* Check again for wrap-around condition on the read pointer. */ if (source >= pipe -> pi_end) /* Move the read pointer to the top of the pipe area. */ source = pipe -> pi_start; /* Determine if the pipe supports variable-length messages. If so, pad bytes are needed to keep UNSIGNED alignment. */ if (pad) { /* Variable-size message. Add pad bytes to the read pointer. */ /* Calculate the number of bytes remaining from the read pointer to the bottom of the pipe. */ copy_size = pipe -> pi_end - source; /* If there is not enough room at the bottom of the pipe, the pad bytes must be wrapped around to the top. */ if (copy_size <= pad) /* Move read pointer to the top of the pipe and make the necessary adjustment. */ source = pipe -> pi_start + (pad - copy_size); else /* There is enough room in the pipe to simply add the the pad bytes to the read pointer. */ source = source + pad; /* Add pad bytes to the available bytes count. */ pipe -> pi_available = pipe -> pi_available + pad; } /* Adjust the actual read pointer. */ pipe -> pi_read = source; /* Increment the number of available bytes. */ pipe -> pi_available = pipe -> pi_available + size; /* Decrement the number of messages in the pipe. */ pipe -> pi_messages--; /* Return the number of bytes received. */ *actual_size = size; #ifdef INCLUDE_PROVIEW _RTProf_DumpPipe(RT_PROF_RECEIVE_FROM_PIPE,pipe,RT_PROF_OK); #endif /* INCLUDE_PROVIEW */ /* Determine if any tasks suspended on a full pipe can be woken up. */ if (pipe -> pi_suspension_list) { /* Pickup the suspension list and examine suspension blocks to see if the message could now fit in the pipe. */ suspend_ptr = pipe -> pi_suspension_list; preempt = NU_FALSE; size = suspend_ptr -> pi_message_size; i = 0; pad = 0; /* Overhead of each pipe message. */ if (!pipe -> pi_fixed_size) { /* Variable messages have one additional word of overhead. */ i = sizeof(UNSIGNED); /* Calculate the number of pad bytes necessary to keep the pipe write pointer on an UNSIGNED data element alignment. */ pad = (((size + sizeof(UNSIGNED) - 1)/sizeof(UNSIGNED)) * sizeof(UNSIGNED)) - size; /* Insure that padding is included in the overhead. */ i = i + ((INT) pad); } while ((suspend_ptr) && ((size + i) <= pipe -> pi_available)) { /* Place the suspended task's message into the pipe. */ /* Setup the source and destination pointers. */ source = suspend_ptr -> pi_message_area; destination = pipe -> pi_write; /* Process according to the type of message supported. */ if (pipe -> pi_fixed_size) { /* Fixed-size messages are supported by this pipe. */ /* Loop to copy the message into the pipe area. */ i = (INT) size; do { *(destination++) = *(source); if ((--i) == 0) break; source++; } while (1); } else { /* Variable-size messages are supported. Processing must check for pipe wrap-around conditions. */ /* Place message size in first location. */ *((UNSIGNED *) destination) = size; destination = destination + sizeof(UNSIGNED); /* Check for a wrap-around condition on the pipe. */ if (destination >= pipe -> pi_end) /* Wrap the write pointer back to the top of the pipe area. */ destination = pipe -> pi_start; /* Decrement the number of bytes remaining for this extra word of overhead. */ pipe -> pi_available = pipe -> pi_available - sizeof(UNSIGNED); /* Calculate the number of bytes remaining from the write pointer to the bottom of the pipe. */ copy_size = pipe -> pi_end - destination; /* Determine if the message needs to be wrapped around the edge of the pipe area. */ if (copy_size >= size) { /* Copy the whole message at once. */ i = (INT) size; do { *(destination++) = *(source); if ((--i) == 0) break; source++; } while (1); } else { /* Copy the first half of the message. */ i = (INT) copy_size; do { *(destination) = *(source++); if ((--i) == 0) break; destination++; } while (1); /* Copy the second half of the message. */ destination = pipe -> pi_start; i = (INT) (size - copy_size); do { *(destination++) = *(source); if ((--i) == 0) break; source++; } while (1); } } /* Check again for wrap-around condition on the write pointer. */ if (destination >= pipe -> pi_end) /* Move the write pointer to the top of the pipe area. */ destination = pipe -> pi_start; /* Determine if the pipe supports variable-length messages. If so, pad bytes are needed to keep UNSIGNED alignment. */ if (pad) { /* Variable-size message. Add pad bytes to the write pointer. */ /* Calculate the number of bytes remaining from the write pointer to the bottom of the pipe. */ copy_size = pipe -> pi_end - destination; /* If there is not enough room at the bottom of the pipe, the pad bytes must be wrapped around to the top. */ if (copy_size <= pad) /* Move write pointer to the top of the pipe and make the necessary adjustment. */ destination = pipe -> pi_start + (pad - copy_size); else /* There is enough room in the pipe to simply add the pad bytes to the write pointer. */ destination = destination + pad; /* Decrement the number of available bytes. */ pipe -> pi_available = pipe -> pi_available - pad; } /* Update the actual write pointer. */ pipe -> pi_write = destination; /* Decrement the number of available bytes. */ pipe -> pi_available = pipe -> pi_available - size; /* Increment the number of messages in the pipe. */ pipe -> pi_messages++; /* Decrement the number of tasks waiting counter. */ pipe -> pi_tasks_waiting--; /* Remove the first suspended block from the list. */ CSC_Remove_From_List((CS_NODE **) &(pipe -> pi_suspension_list), &(suspend_ptr -> pi_suspend_link)); /* Return a successful status. */ suspend_ptr -> pi_return_status = NU_SUCCESS; /* Resume the suspended task. */ preempt = preempt | TCC_Resume_Task((NU_TASK *) suspend_ptr -> pi_suspended_task, NU_PIPE_SUSPEND); /* Setup suspend pointer to the head of the list. */ suspend_ptr = pipe -> pi_suspension_list; /* Determine if there really is another suspended block. If there is and the pipe supports variable length messages, calculate new size and padding parameters. */ if ((suspend_ptr) && (!pipe -> pi_fixed_size)) { /* Get the next message size. */ size = suspend_ptr -> pi_message_size; /* Variable messages have one additional word of overhead. */ i = sizeof(UNSIGNED); /* Calculate the number of pad bytes necessary to keep the pipe write pointer on an UNSIGNED data element alignment. */ pad = (((size + sizeof(UNSIGNED) - 1)/sizeof(UNSIGNED)) * sizeof(UNSIGNED)) - size; /* Insure that padding is included in the overhead. */ i = i + ((INT) pad); } } /* Determine if a preempt condition is present. */ if (preempt) /* Transfer control to the system if the resumed task function detects a preemption condition. */ TCT_Control_To_System(); } } else { /* pipe is empty. Determine if the task wants to suspend. */ if (suspend) { /* Increment the number of tasks waiting on the pipe counter. */ pipe -> pi_tasks_waiting++; #ifdef INCLUDE_PROVIEW _RTProf_DumpPipe(RT_PROF_RECEIVE_FROM_PIPE,pipe,RT_PROF_WAIT); #endif /* INCLUDE_PROVIEW */ /* Setup the suspend block and suspend the calling task. */ suspend_ptr = &suspend_block; suspend_ptr -> pi_pipe = pipe; suspend_ptr -> pi_suspend_link.cs_next = NU_NULL; suspend_ptr -> pi_suspend_link.cs_previous = NU_NULL; suspend_ptr -> pi_message_area = (BYTE_PTR) message; suspend_ptr -> pi_message_size = size; task = (TC_TCB *) TCT_Current_Thread(); suspend_ptr -> pi_suspended_task = task; /* Determine if priority or FIFO suspension is associated with the pipe. */ if (pipe -> pi_fifo_suspend) { /* FIFO suspension is required. Link the suspend block into the list of suspended tasks on this pipe. */ CSC_Place_On_List((CS_NODE **) &(pipe -> pi_suspension_list), &(suspend_ptr -> pi_suspend_link)); } else { /* Get the priority of the current thread so the suspend block can be placed in the appropriate place. */ suspend_ptr -> pi_suspend_link.cs_priority = TCC_Task_Priority(task); CSC_Priority_Place_On_List((CS_NODE **) &(pipe -> pi_suspension_list), &(suspend_ptr -> pi_suspend_link)); } /* Finally, suspend the calling task. Note that the suspension call automatically clears the protection on the pipe. */ TCC_Suspend_Task((NU_TASK *) task, NU_PIPE_SUSPEND, PIC_Cleanup, suspend_ptr, suspend); /* Pickup the status of the request. */ status = suspend_ptr -> pi_return_status; *actual_size = suspend_ptr -> pi_actual_size; } else { /* Return a status of NU_PIPE_EMPTY because there are no messages in the pipe. */ status = NU_PIPE_EMPTY; #ifdef INCLUDE_PROVIEW _RTProf_DumpPipe(RT_PROF_RECEIVE_FROM_PIPE,pipe,RT_PROF_FAIL); #endif /* INCLUDE_PROVIEW */ } } /* Release protection against access to the pipe. */ TCT_Unprotect(); /* Return to user mode */ NU_USER_MODE(); /* Return the completion status. */ return(status); } /*************************************************************************/ /* */ /* FUNCTION */ /* */ /* PIC_Cleanup */ /* */ /* DESCRIPTION */ /* */ /* This function is responsible for removing a suspension block */ /* from a pipe. It is not called unless a timeout or a task */ /* terminate is in progress. Note that protection is already in */ /* effect - the same protection at suspension time. This routine */ /* must be called from Supervisor mode in Supervisor/User mode */ /* switching kernels. */ /* */ /* CALLED BY */ /* */ /* TCC_Timeout Task timeout */ /* TCC_Terminate Task terminate */ /* */ /* CALLS */ /* */ /* CSC_Remove_From_List Remove suspend block from */ /* the suspension list */ /* */ /* INPUTS */ /* */ /* information Pointer to suspend block */ /* */ /* OUTPUTS */ /* */ /* None */ /* */ /* HISTORY */ /* */ /* DATE REMARKS */ /* */ /* 03-01-1993 Created initial version 1.0 */ /* 04-19-1993 Verified version 1.0 */ /* */ /*************************************************************************/ VOID PIC_Cleanup(VOID *information) { PI_SUSPEND *suspend_ptr; /* Suspension block pointer */ NU_SUPERV_USER_VARIABLES /* Switch to supervisor mode */ NU_SUPERVISOR_MODE(); /* Use the information pointer as a suspend pointer. */ suspend_ptr = (PI_SUSPEND *) information; /* By default, indicate that the service timed-out. It really does not matter if this function is called from a terminate request since the task does not resume. */ suspend_ptr -> pi_return_status = NU_TIMEOUT; /* Decrement the number of tasks waiting counter. */ (suspend_ptr -> pi_pipe) -> pi_tasks_waiting--; /* Determine if the suspend block is one the urgent list. */ if ((suspend_ptr -> pi_pipe) -> pi_urgent_list) { /* Unlink the suspend block from the urgent list. */ CSC_Remove_From_List((CS_NODE **) &((suspend_ptr -> pi_pipe) -> pi_urgent_list), &(suspend_ptr -> pi_suspend_link)); } else { /* Unlink the suspend block from the suspension list. */ CSC_Remove_From_List((CS_NODE **) &((suspend_ptr -> pi_pipe) -> pi_suspension_list), &(suspend_ptr -> pi_suspend_link)); } /* Return to user mode */ NU_USER_MODE(); }