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/* tick.c -- Simulation of OpenRISC 1000 tick timer
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/* tick.c -- Simulation of OpenRISC 1000 tick timer
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Copyright (C) 1999 Damjan Lampret, lampret@opencores.org
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Copyright (C) 1999 Damjan Lampret, lampret@opencores.org
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Copyright (C) 2005 György `nog' Jeney, nog@sdf.lonestar.org
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This file is part of OpenRISC 1000 Architectural Simulator.
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This file is part of OpenRISC 1000 Architectural Simulator.
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This program is free software; you can redistribute it and/or modify
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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it under the terms of the GNU General Public License as published by
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#include "debug.h"
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#include "debug.h"
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DEFAULT_DEBUG_CHANNEL(tick);
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DEFAULT_DEBUG_CHANNEL(tick);
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/* When did the timer start to count */
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/* When did the timer start to count */
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int cycles_start = 0;
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long long cycles_start = 0;
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/* TT Count Register */
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/* Indicates if the timer is actually counting. Needed to simulate one-shot
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unsigned long ttcr;
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* mode correctly */
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int tick_count;
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/* TT Mode Register */
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unsigned long ttmr;
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/* Reset. It initializes TTCR register. */
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/* Reset. It initializes TTCR register. */
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void tick_reset(void)
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void tick_reset(void)
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{
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{
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if (config.sim.verbose)
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if (config.sim.verbose)
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PRINTF("Resetting Tick Timer.\n");
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PRINTF("Resetting Tick Timer.\n");
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mtspr(SPR_TTCR, 0);
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cpu_state.sprs[SPR_TTCR] = 0;
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mtspr(SPR_TTMR, 0);
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cpu_state.sprs[SPR_TTMR] = 0;
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tick_count = 0;
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}
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}
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/* Job handler for tick timer */
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/* Raises a timer exception */
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void tick_job (void *param)
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void tick_raise_except(void *dat)
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{
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{
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int mode = (ttmr & SPR_TTMR_M) >> 30;
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TRACE("tick_job param: %i, mode: %i at %lli (%lli)\n", (int)param, mode,
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runtime.sim.cycles, runtime.cpu.instructions);
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switch (mode) {
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case 1:
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if (!param) {
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cpu_state.sprs[SPR_TTCR] = ttcr = 0;
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cycles_start = runtime.sim.cycles - ttcr;
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TRACE("Scheduleing timer job for %li\n", (ttmr & SPR_TTMR_PERIOD) - ttcr);
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SCHED_ADD(tick_job, (void *)0, (ttmr & SPR_TTMR_PERIOD) - ttcr);
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}
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case 2:
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if (ttmr & SPR_TTMR_IE) {
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cpu_state.sprs[SPR_TTMR] |= SPR_TTMR_IP;
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cpu_state.sprs[SPR_TTMR] |= SPR_TTMR_IP;
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/* be sure not to issue timer exception if an exception occured before it */
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/* be sure not to issue a timer exception if an exception occured before it */
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if ((mfspr(SPR_SR) & SPR_SR_TEE) == SPR_SR_TEE)
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if(cpu_state.sprs[SPR_SR] & SPR_SR_TEE)
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except_handle(EXCEPT_TICK, mfspr(SPR_EEAR_BASE));
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except_handle(EXCEPT_TICK, cpu_state.sprs[SPR_EEAR_BASE]);
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/* Reschedule unconditionally, since we have to raise the exception until
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* TTMR_IP has been cleared */
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SCHED_ADD(tick_raise_except, NULL, 1);
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}
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/* Restarts the tick timer */
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void tick_restart(void *dat)
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{
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cpu_state.sprs[SPR_TTCR] = 0;
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cycles_start = runtime.sim.cycles;
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TRACE("Scheduleing timer restart job for %"PRIdREG"\n",
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cpu_state.sprs[SPR_TTMR] & SPR_TTMR_PERIOD);
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SCHED_ADD(tick_restart, NULL, cpu_state.sprs[SPR_TTMR] & SPR_TTMR_PERIOD);
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}
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/* Stops the timer */
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void tick_one_shot(void *dat)
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{
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TRACE("Stopping one-shot timer\n");
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cpu_state.sprs[SPR_TTCR] = cpu_state.sprs[SPR_TTMR] & SPR_TTMR_PERIOD;
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tick_count = 0;
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}
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/* Schedules the timer jobs */
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static void sched_timer_job(uorreg_t prev_ttmr)
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{
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uorreg_t ttmr = cpu_state.sprs[SPR_TTMR];
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uint32_t match_time = ttmr & SPR_TTMR_PERIOD;
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uint32_t ttcr_period = spr_read_ttcr() & SPR_TTCR_PERIOD;
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/* Remove previous jobs if they exists */
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if(prev_ttmr & SPR_TTMR_IE)
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SCHED_FIND_REMOVE(tick_raise_except, NULL);
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switch(prev_ttmr & SPR_TTMR_M) {
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case SPR_TTMR_RT:
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SCHED_FIND_REMOVE(tick_restart, NULL);
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break;
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case SPR_TTMR_SR:
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SCHED_FIND_REMOVE(tick_one_shot, NULL);
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break;
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}
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if(match_time >= ttcr_period)
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match_time -= ttcr_period;
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else
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else
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/* If TEE is currently not set we have to pend tick exception
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match_time += (0xfffffffu - ttcr_period) + 1;
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by rescheduling. */
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SCHED_ADD(tick_job, (void *)1, 1);
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TRACE("Cycles to go until match: %"PRIu32" (0x%"PRIx32")\n", match_time,
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match_time);
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switch(ttmr & SPR_TTMR_M) {
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case 0: /* Disabled timer */
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TRACE("Scheduleing exception when timer match (in disabled mode).\n");
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if(!match_time && (ttmr & SPR_TTMR_IE) && !(ttmr & SPR_TTMR_IP))
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SCHED_ADD(tick_raise_except, NULL, 0);
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break;
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case SPR_TTMR_RT: /* Auto-restart timer */
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TRACE("Scheduleing auto-restarting timer.\n");
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SCHED_ADD(tick_restart, NULL, match_time);
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if((ttmr & SPR_TTMR_IE) && !(ttmr & SPR_TTMR_IP))
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SCHED_ADD(tick_raise_except, NULL, match_time);
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break;
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case SPR_TTMR_SR: /* One-shot timer */
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TRACE("Scheduleing one-shot timer.\n");
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if(tick_count) {
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SCHED_ADD(tick_one_shot, NULL, match_time);
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if((ttmr & SPR_TTMR_IE) && !(ttmr & SPR_TTMR_IP))
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SCHED_ADD(tick_raise_except, NULL, match_time);
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}
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}
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break;
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break;
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case SPR_TTMR_CR: /* Continuos timer */
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TRACE("Scheduleing exception when timer match (in cont. mode).\n");
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if((ttmr & SPR_TTMR_IE) && !(ttmr & SPR_TTMR_IP))
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SCHED_ADD(tick_raise_except, NULL, match_time);
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}
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}
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}
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}
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/* Starts the tick timer. This function is called by a write to ttcr spr register */
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/* Handles a write to the ttcr spr */
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void spr_write_ttcr (uorreg_t value)
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void spr_write_ttcr (uorreg_t value)
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{
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{
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unsigned mode = (ttmr & SPR_TTMR_M) >> 30;
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TRACE("set ttcr = %"PRIxREG"\n", value);
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TRACE("set ttcr = %"PRIxREG"\n", value);
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ttcr = value;
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cycles_start = runtime.sim.cycles - value;
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/* Remove previous if it exists */
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TRACE("Removeing scheduled jobs\n");
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sched_timer_job(cpu_state.sprs[SPR_TTMR]);
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SCHED_FIND_REMOVE(tick_job, (void *)0);
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SCHED_FIND_REMOVE(tick_job, (void *)1);
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if (mode == 1 || mode == 2) {
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TRACE("Scheduleing timer job for %li\n", (ttmr & SPR_TTMR_PERIOD) - ttcr);
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SCHED_ADD(tick_job, (void *)0, (ttmr & SPR_TTMR_PERIOD) - ttcr);
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cycles_start = runtime.sim.cycles - ttcr;
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}
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}
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}
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void spr_write_ttmr (uorreg_t value)
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/* Value is the *previous* value of SPR_TTMR. The new one can be found in
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{
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* cpu_state.sprs[SPR_TTMR] */
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TRACE("set ttmr = %"PRIxREG"\n", value);
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void spr_write_ttmr (uorreg_t prev_val)
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ttmr = value;
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{
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/* Handle the modes properly. */
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uorreg_t value = cpu_state.sprs[SPR_TTMR];
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switch((ttmr & SPR_TTMR_M) >> 30) {
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case 0: /* Timer is disabled */
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TRACE("set ttmr = %"PRIxREG" (previous: %"PRIxREG")\n", value, prev_val);
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TRACE("Removeing scheduled jobs\n");
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SCHED_FIND_REMOVE(tick_job, (void *)0);
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if(value & SPR_TTMR_IP) {
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SCHED_FIND_REMOVE(tick_job, (void *)1);
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if(prev_val & SPR_TTMR_IP)
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break;
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/* SPR_TTMR_IP has not been cleared, continue sending timer interrupts */
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case 1: /* Timer should auto restart */
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SCHED_ADD(tick_raise_except, NULL, 0);
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cpu_state.sprs[SPR_TTCR] = ttcr = 0;
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else
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cycles_start = runtime.sim.cycles;
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/* Code running on or1k can't set SPR_TTMR_IP so make sure it isn't */
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TRACE("Removeing scheduled jobs\n");
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cpu_state.sprs[SPR_TTMR] &= ~SPR_TTMR_IP;
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SCHED_FIND_REMOVE(tick_job, (void *)0);
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SCHED_FIND_REMOVE(tick_job, (void *)1);
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TRACE("Scheduleing timer job for %li\n", (ttmr & SPR_TTMR_PERIOD) - ttcr);
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SCHED_ADD(tick_job, (void *)0, (ttmr & SPR_TTMR_PERIOD) - ttcr);
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break;
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case 2: /* Stop the timer when match */
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TRACE("Removeing scheduled jobs\n");
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SCHED_FIND_REMOVE(tick_job, (void *)0);
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SCHED_FIND_REMOVE(tick_job, (void *)1);
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break;
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case 3: /* Timer keeps running -- do nothing*/
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break;
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}
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}
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/* If the timer was already disabled, ttcr should not be updated */
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if(tick_count)
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cpu_state.sprs[SPR_TTCR] = runtime.sim.cycles - cycles_start;
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cycles_start = runtime.sim.cycles - cpu_state.sprs[SPR_TTCR];
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tick_count = value & SPR_TTMR_M;
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if((tick_count == 0xc0000000) &&
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(cpu_state.sprs[SPR_TTCR] == (value & SPR_TTMR_PERIOD)))
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tick_count = 0;
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sched_timer_job(prev_val);
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}
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}
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uorreg_t spr_read_ttcr (void)
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uorreg_t spr_read_ttcr (void)
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{
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{
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TRACE("read ttcr %lli\n", runtime.sim.cycles - cycles_start);
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uorreg_t ret;
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return runtime.sim.cycles - cycles_start;
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if(!tick_count)
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/* Report the time when the counter stoped (and don't carry on counting) */
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ret = cpu_state.sprs[SPR_TTCR];
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else
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ret = runtime.sim.cycles - cycles_start;
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TRACE("read ttcr %"PRIdREG" (0x%"PRIxREG")\n", ret, ret);
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return ret;
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}
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}
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No newline at end of file
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No newline at end of file
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