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220 lines
7.9 KiB
220 lines
7.9 KiB
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// scheduling algorithm for split periodic
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#ifndef __SCHED_H__
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#define __SCHED_H__
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#define MAXCEPS 30
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// all times are in units of bytes
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#define FS_BYTES_PER_MICROFRAME 188
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#define MICROFRAMES_PER_FRAME 8
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#define FS_SOF 6 // number of byte times allocated to an SOF packet at the beginning of a frame
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//#define MAXFRAMES 8 // scheduling window for budget tracking, periods longer than
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#define MAXFRAMES 32 // scheduling window for budget tracking, periods longer than
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// this are reduced to this. Also impacts space required for
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// tracking data structures. Otherwise fairly arbitrary.
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#define MAXMICROFRAMES (MAXFRAMES * 8)
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// 4 byte sync, 4 byte split token, 1 byte EOP, 11 byte ipg, plus
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// 4 byte sync, 3 byte regular token, 1 byte EOP, 11 byte ipg
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#define HS_SPLIT_SAME_OVERHEAD 39
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// 4 byte sync, 4 byte split token, 1 byte EOP, 11 byte ipg, plus
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// 4 byte sync, 3 byte regular token, 1 byte EOP, 1 byte bus turn
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#define HS_SPLIT_TURN_OVERHEAD 29
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// 4 byte sync, 1 byte PID, 2 bytes CRC16, 1 byte EOP, 11 byte ipg
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#define HS_DATA_SAME_OVERHEAD 19
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// 4 byte sync, 1 byte PID, 2 bytes CRC16, 1 byte EOP, 1 byte bus turn
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#define HS_DATA_TURN_OVERHEAD 9
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// 4 byte sync, 1 byte PID, 1 byte EOP, 1 byte bus turn
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#define HS_HANDSHAKE_OVERHEAD 7
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//#define HS_MAX_PERIODIC_ALLOCATION 6000 // floor(0.8*7500)
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#define HS_MAX_PERIODIC_ALLOCATION 7000 // floor(0.8*7500)
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// This could actually be a variable based on an HC implementation
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// some measurements have shown 3?us between transactions or about 3% of a microframe
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// which is about 200+ byte times. We'll use about half that for budgeting purposes.
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#define HS_HC_THINK_TIME 100
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// 4 byte sync, 3 byte regular token, 1 byte EOP, 11 byte ipg
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#define HS_TOKEN_SAME_OVERHEAD 19
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// 4 byte sync, 3 byte regular token, 1 byte EOP, 1 byte bus turn
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#define HS_TOKEN_TURN_OVERHEAD 9
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// TOKEN: 1 byte sync, 3 byte token, 3 bit EOP, 1 byte ipg
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// DATA: 1 byte sync, 1 byte PID, 2 bytes CRC16, 3 bit EOP, 1 byte ipg
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// HANDSHAKE: 1 byte sync, 1 byte PID, 3 bit EOP, 1 byte ipg
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#define FS_ISOCH_OVERHEAD 9
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#define FS_INT_OVERHEAD 13
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//#define LS_INT_OVERHEAD (19*8)
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#define LS_INT_OVERHEAD ((14 *8) + 5)
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#define HUB_FS_ADJ 30 // periodic allocation at beginning of frame for use by hubs, maximum allowable is 60 bytes
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#define FS_MAX_PERIODIC_ALLOCATION (1157) // floor(0.9*1500/1.16)
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#define FS_BS_MAX_PERIODIC_ALLOCATION 1350 // floor(0.9*1500), includes bitstuffing allowance (for HC classic allocation)
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// byte time to qualify as a large FS isoch transaction
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// 673 = 1023/1.16 (i.e. 881) - 1microframe (188) - adj (30) or
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// 1/2 of max allocation in this case
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// #define LARGEXACT (881-FS_BYTES_PER_MICROFRAME)
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#define LARGEXACT (579)
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typedef struct _Endpoint *PEndpoint;
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typedef struct _frame_rec
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{
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unsigned time_used:16; // The number of bytes that are budgeted for all endpoints in this frame
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PEndpoint allocated_large; // endpoint if xact over LARGEXACT bytes is allocated in this frame
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PEndpoint isoch_ehead; // many frames can point to the same endpoint. endpoints are linked
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PEndpoint int_ehead; // in longest to shortest period.
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//
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// NOTE: always start with a "dummy" endpoint for SOF on the lists to avoid empty list corner condition
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//
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} frame_rec;
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typedef struct _HC *PHC;
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typedef struct _TT *PTT;
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typedef enum {bulk, control, interrupt, isoch} eptype;
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#define HSSPEED 2
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#define FSSPEED 1
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#define LSSPEED 0
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#define INDIR 0
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#define OUTDIR 1
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typedef struct _Endpoint
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{
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unsigned type;
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// These fields have static information that is valid/constant as long as an
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// endpoint is configured
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unsigned max_packet:16; // maximum number of data bytes allowed for this
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// endpoint. 0-8 for LS_int, 0-64 for FS_int,
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// 0-1023 for FS_isoch.
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unsigned period:16; // desired period of transactions, assumed to be a power of 2
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eptype ep_type:4;
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unsigned direction:1;
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unsigned speed:2;
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unsigned moved_this_req:1; // 1 when this endpoint has been changed during this allocation request
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PTT mytt; // the TT that roots this classic device.
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// These fields hold dynamically calculated information that changes as (other)
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// endpoints are added/removed.
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unsigned calc_bus_time:16; // bytes of FS/LS bus time this endpoint requires
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// including overhead. This can be calculated once.
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unsigned start_time:16; // classic bus time at which this endpoint is budgeted to occupy the classic bus
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unsigned actual_period:16; // requested period can be modified:
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// 1. when period is greater than scheduling window (MAXFRAMES)
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// 2. if period is reduced (not currently done by algorithm)
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unsigned start_frame:8; // first bus frame that is allocated to this endpoint.
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int start_microframe:8; // first bus microframe (in a frame) that can have a
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// start-split for this ep.
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// Complete-splits always start 2 microframes after a
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// start-split.
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unsigned num_starts:4; // the number of start splits.
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unsigned num_completes:4; // the number of complete splits.
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/* The numbers above could be (better?) represented as bitmasks. */
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/* corner conditions above: coder beware!!
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patterns can have the last CS in the "next" frame
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This is indicated in this design when:
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(start_microframe + num_completes + 1) > 7
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patterns can have the first SS in the previous frame
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This is indicated in this design when:
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start_microframe = -1
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*/
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PEndpoint next_ep; // pointer to next (faster/equal period) endpoint in budget
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int id:16; // not needed for real budgeter
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unsigned saved_period:16; // used during period promotion to hold original period
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unsigned promoted_this_time:1;
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} Endpoint;
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typedef struct _TT
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{
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unsigned HS_split_data_time[MAXFRAMES][MICROFRAMES_PER_FRAME]; // HS data bytes used for split completes
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// the above time tracks the data time for all devices rooted in this TT.
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// when the time is below 188 in a microframe, that time is allocated in the
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// HS microframe (in the HS HC budget). When the time is greater than 188
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// only 188 byte times (bit stuffed) is allocated on the HS microframe budget.
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unsigned num_starts[MAXFRAMES][MICROFRAMES_PER_FRAME];
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frame_rec frame_budget[MAXFRAMES];
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PHC myHC;
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unsigned think_time; // TT reports it inter transaction "think" time. Keep it here.
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unsigned allocation_limit; // maximum allocation allowed for this TT's classic bus
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struct _Endpoint isoch_head[MAXFRAMES];
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struct _Endpoint int_head[MAXFRAMES];
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} TT;
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typedef struct _microframe_rec
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{
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unsigned time_used;
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} microframe_rec;
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typedef struct _HC
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{
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microframe_rec HS_microframe_info[MAXFRAMES][MICROFRAMES_PER_FRAME]; // HS bus time allocated to
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//this host controller
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PTT tthead; // head of list of TTs attached to this HC
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unsigned thinktime;
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unsigned allocation_limit; // maximum allocation allowed for this HC
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int speed; // HS or FS
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} HC;
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#if 0
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typedef struct _command {
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char cmd_code;
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int endpoint_number;
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} Cmd_t;
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#endif
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/* protoypes */
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void init_hc(PHC myHC);
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Set_endpoint(
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PEndpoint ep,
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eptype t,
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unsigned d,
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unsigned s,
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unsigned p,
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unsigned m,
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TT *thistt
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);
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int Allocate_time_for_endpoint(
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PEndpoint ep,
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PEndpoint changed_ep_list[],
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int *max_changed_eps
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);
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void
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init_tt(PHC myHC, PTT myTT);
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void
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Deallocate_time_for_endpoint(
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PEndpoint ep, // endpoint that needs to be removed (bus time deallocated)
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PEndpoint changed_ep_list[], // pointer to array to set (on return) with list of
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// changed endpoints
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int *max_changed_eps // input: maximum size of (returned) list
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// on return: number of changed endpoints
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);
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#endif // __SCHED_H__
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