FreeCalypso > hg > ffs-editor
diff src/nucleus/pis.c @ 0:92470e5d0b9e
src: partial import from FC Selenite
| author | Mychaela Falconia <falcon@freecalypso.org> |
|---|---|
| date | Fri, 15 May 2020 01:28:16 +0000 |
| parents | |
| children |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/nucleus/pis.c Fri May 15 01:28:16 2020 +0000 @@ -0,0 +1,1130 @@ +/*************************************************************************/ +/* */ +/* 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 */ +/* */ +/* pis.c Nucleus PLUS 1.14 */ +/* */ +/* COMPONENT */ +/* */ +/* PI - Pipe Management */ +/* */ +/* DESCRIPTION */ +/* */ +/* This file contains the supplemental routines for the pipe */ +/* management component. */ +/* */ +/* DATA STRUCTURES */ +/* */ +/* None */ +/* */ +/* FUNCTIONS */ +/* */ +/* PIS_Reset_Pipe Reset a pipe */ +/* PIS_Send_To_Front_Of_Pipe Send message to pipe's front */ +/* PIS_Broadcast_To_Pipe Broadcast a message to pipe */ +/* */ +/* 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 */ +/* */ +/* 03-01-1994 Created initial version 1.1 from */ +/* routines originally in core */ +/* */ +/* 03-18-1994 Verified version 1.1 */ +/* 04-17-1996 updated to version 1.2 */ +/* 02-04-1998 Corrected SPR434 resulting in */ +/* version 1.2a. */ +/* 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 */ +/* */ +/* PIS_Reset_Pipe */ +/* */ +/* DESCRIPTION */ +/* */ +/* This function resets the specified pipe back to the original */ +/* state. Any messages in the pipe are discarded. Also, any */ +/* tasks currently suspended on the pipe are resumed with the */ +/* reset status. */ +/* */ +/* CALLED BY */ +/* */ +/* Application */ +/* PISE_Reset_Pipe Error checking shell */ +/* */ +/* CALLS */ +/* */ +/* [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_System_Protect Protect against system access*/ +/* TCT_Unprotect Release protection */ +/* */ +/* INPUTS */ +/* */ +/* pipe_ptr Pipe control block pointer */ +/* */ +/* OUTPUTS */ +/* */ +/* NU_SUCCESS */ +/* */ +/* HISTORY */ +/* */ +/* NAME 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, fixed read and write */ +/* pointers to both point at the */ +/* start, resulting in version 1.1 */ +/* */ +/* 03-18-1994 Verified version 1.1 */ +/* 02-04-1998 Corrected SPR434. */ +/* */ +/*************************************************************************/ +STATUS PIS_Reset_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 suspend block pointer*/ +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_RESET_PIPE_ID, (UNSIGNED) pipe, + (UNSIGNED) 0, (UNSIGNED) 0); + +#endif + + /* Protect against access to the pipe. */ + TCT_System_Protect(); + + /* Pickup the suspended task suspension list. */ + suspend_ptr = pipe -> pi_suspension_list; + + /* Walk the chain task(s) currently suspended on the pipe. */ + preempt = 0; + while (suspend_ptr) + { + + /* Resume the suspended task. Insure that the status returned is + NU_PIPE_RESET. */ + suspend_ptr -> pi_return_status = NU_PIPE_RESET; + + /* 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 + + /* Position the suspend pointer to the next block. */ + suspend_ptr = next_ptr; + } + + /* 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) + { + + /* Resume the suspended task. Insure that the status returned is + NU_PIPE_RESET. */ + suspend_ptr -> pi_return_status = NU_PIPE_RESET; + + /* 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 the suspend pointer to the next active block. */ + suspend_ptr = next_ptr; + } + + /* Initialize various elements of the pipe. */ + pipe -> pi_available = pipe -> pi_end - pipe -> pi_start; + pipe -> pi_messages = 0; + pipe -> pi_read = pipe -> pi_start; + pipe -> pi_write = pipe -> pi_start; + pipe -> pi_tasks_waiting = 0; + pipe -> pi_suspension_list = NU_NULL; + pipe -> pi_urgent_list = NU_NULL; + +#ifdef INCLUDE_PROVIEW + _RTProf_DumpPipe(RT_PROF_RESET_PIPE,pipe,RT_PROF_OK); +#endif /* INCLUDE_PROVIEW */ + + /* 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 pipe. */ + TCT_Unprotect(); + + /* Return to user mode */ + NU_USER_MODE(); + + /* Return a successful completion. */ + return(NU_SUCCESS); +} + + +/*************************************************************************/ +/* */ +/* FUNCTION */ +/* */ +/* PIS_Send_To_Front_Of_Pipe */ +/* */ +/* DESCRIPTION */ +/* */ +/* This function sends a message to the front of the specified */ +/* message pipe. The message length is determined by the caller. */ +/* If there are any tasks suspended on the pipe for a message, the */ +/* message is copied into the message area of the first waiting */ +/* task and that task is resumed. If there is enough room in the */ +/* pipe, the message is copied in front of all other messages. */ +/* If there is not enough room in the pipe, suspension of the */ +/* caller is possible. */ +/* */ +/* CALLED BY */ +/* */ +/* Application */ +/* PISE_Send_To_Front_Of_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 */ +/* [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 PIS_Send_To_Front_Of_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_FRONT_OF_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 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_FRONT_OF_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; + + /* Place the task on the urgent message suspension list. */ + CSC_Place_On_List((CS_NODE **) &(pipe -> pi_urgent_list), + &(suspend_ptr -> pi_suspend_link)); + + /* Move the head pointer of the list to make this suspension the + first in the list. */ + pipe -> pi_urgent_list = (PI_SUSPEND *) + (pipe -> pi_urgent_list) -> pi_suspend_link.cs_previous; + + /* 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_FRONT_OF_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_FRONT_OF_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_read; + + /* Process according to the type of message supported. */ + if (pipe -> pi_fixed_size) + { + + /* Fixed-size message pipe. */ + + /* Determine if the read pointer is at the top of the pipe + area. */ + if (destination == pipe -> pi_start) + + /* Prepare to place the message in the lower part of the + pipe area. */ + destination = pipe -> pi_end - size; + else + + /* Backup the length of the message from the current + read pointer. */ + destination = destination - size; + + /* Adjust the actual read pointer before the copy is done. */ + pipe -> pi_read = destination; + + /* Copy the message into the pipe area. */ + i = (INT) size; + do + { + *(destination++) = *(source); + if ((--i) == 0) + break; + source++; + } while (1); + } + else + { + + /* Variable-length message pipe. */ + + /* Calculate the number of bytes remaining from the write + pointer to the bottom of the pipe. */ + copy_size = destination - pipe -> pi_start; + + /* Determine if part of the message needs to be placed at the + bottom of the pipe area. */ + if (copy_size < (size + i)) + + /* Compute the starting location for the message. */ + destination = pipe -> pi_end - ((size + i) - copy_size); + else + + /* Compute the starting location for the message. */ + destination = destination - (size + i); + + /* Adjust the actual pipe read pointer also. */ + pipe -> pi_read = destination; + + /* 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 + pad)) + { + + /* 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; + + /* Determine if there is anything left to copy. */ + if (size > copy_size) + { + /* Yes, there is something to copy. */ + i = (INT) (size - copy_size); + do + { + *(destination++) = *(source); + if ((--i) == 0) + break; + source++; + } while (1); + } + } + /* Decrement the number of available bytes. */ + pipe -> pi_available = pipe -> pi_available - pad; + } + + /* 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_FRONT_OF_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 */ +/* */ +/* PIS_Broadcast_To_Pipe */ +/* */ +/* DESCRIPTION */ +/* */ +/* This function sends a message to all tasks waiting for a message */ +/* from the specified pipe. If there are no tasks waiting for a */ +/* message the service performs like a standard send request. */ +/* */ +/* CALLED BY */ +/* */ +/* Application */ +/* PISE_Broadcast_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 PIS_Broadcast_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 */ +UNSIGNED pad = 0; /* Number of pad bytes */ +R4 INT i; /* Working counter */ +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_BROADCAST_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 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_BROADCAST_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_BROADCAST_TO_PIPE,pipe,RT_PROF_FAIL); +#endif /* INCLUDE_PROVIEW */ + + } + } + else + { + +#ifdef INCLUDE_PROVIEW + _RTProf_DumpPipe(RT_PROF_BROADCAST_TO_PIPE,pipe,RT_PROF_OK); +#endif /* INCLUDE_PROVIEW */ + + /* Determine if a task is waiting on an empty pipe. */ + if ((pipe -> pi_suspension_list) && (pipe -> pi_messages == 0)) + { + + /* Yes, one or more tasks are waiting for a message from this + pipe. */ + preempt = 0; + do + { + + /* Decrement the number of tasks waiting on pipe. */ + pipe -> pi_tasks_waiting--; + + /* 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 = preempt | + TCC_Resume_Task((NU_TASK *) suspend_ptr -> pi_suspended_task, + NU_PIPE_SUSPEND); + + /* Move the suspend pointer to the next node, which is now + at the head of the list. */ + suspend_ptr = pipe -> pi_suspension_list; + } while (suspend_ptr); + + /* 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++; + } + } + + /* Release protection against access to the pipe. */ + TCT_Unprotect(); + + /* Return to user mode */ + NU_USER_MODE(); + + /* Return the completion status. */ + return(status); +} + + + + + + +