From 70891355ec2c4084209f22726a3de8ffe58fdab6 Mon Sep 17 00:00:00 2001 From: Rodrigo Arias Date: Mon, 30 May 2022 19:27:59 +0200 Subject: [PATCH] Use only a stack of tasks for nosv The running task is inferred from the task on top of the stack. Also, allow a nested task to execute when there are others in the stack. --- emu.h | 6 ++---- emu_nosv.c | 41 ++++++++++++++++++++++------------------- 2 files changed, 24 insertions(+), 23 deletions(-) diff --git a/emu.h b/emu.h index 019e01a..d955640 100644 --- a/emu.h +++ b/emu.h @@ -286,10 +286,8 @@ struct ovni_ethread { /* FIXME: Use a table with registrable pointers to custom data * structures */ - /* nosv task */ - struct nosv_task *task; - /* nosv effective task, which is what is currently executing */ - struct nosv_task *running_task; + /* nOS-V stack of tasks: points to the runnable task. */ + struct nosv_task *task_stack; /* Channels are used to output the emulator state in PRV */ struct ovni_chan chan[CHAN_MAX]; diff --git a/emu_nosv.c b/emu_nosv.c index 1d09782..47a86b9 100644 --- a/emu_nosv.c +++ b/emu_nosv.c @@ -113,9 +113,10 @@ pre_task_create(struct ovni_emu *emu) static void pre_task_execute(struct ovni_emu *emu) { - struct nosv_task *task; + struct nosv_task *task, *top; int taskid; + top = emu->cur_thread->task_stack; taskid = emu->cur_ev->payload.i32[0]; HASH_FIND_INT(emu->cur_proc->tasks, &taskid, task); @@ -132,13 +133,16 @@ pre_task_execute(struct ovni_emu *emu) if(emu->cur_thread->state != TH_ST_RUNNING) die("thread state is not running\n"); - if(emu->cur_thread->task != NULL) - die("thread already has a task\n"); + if(top == task) + die("thread already has assigned task %d\n", taskid); + + if(top && top->state != TASK_ST_RUNNING) + die("cannot execute a nested task from a non-running task\n"); task->state = TASK_ST_RUNNING; task->thread = emu->cur_thread; - DL_PREPEND(emu->cur_thread->task, task); - emu->cur_thread->running_task = task; + + DL_PREPEND(emu->cur_thread->task_stack, task); dbg("task id=%d runs now\n", task->id); } @@ -146,9 +150,10 @@ pre_task_execute(struct ovni_emu *emu) static void pre_task_pause(struct ovni_emu *emu) { - struct nosv_task *task; + struct nosv_task *task, *top; int taskid; + top = emu->cur_thread->task_stack; taskid = emu->cur_ev->payload.i32[0]; HASH_FIND_INT(emu->cur_proc->tasks, &taskid, task); @@ -162,14 +167,12 @@ pre_task_pause(struct ovni_emu *emu) if(emu->cur_thread->state != TH_ST_RUNNING) die("thread state is not running\n"); - if(emu->cur_thread->task != task) + if(top != task) die("thread has assigned a different task\n"); if(emu->cur_thread != task->thread) die("task is assigned to a different thread\n"); - emu->cur_thread->running_task = NULL; - task->state = TASK_ST_PAUSED; dbg("task id=%d pauses\n", task->id); @@ -178,9 +181,10 @@ pre_task_pause(struct ovni_emu *emu) static void pre_task_resume(struct ovni_emu *emu) { - struct nosv_task *task; + struct nosv_task *task, *top; int taskid; + top = emu->cur_thread->task_stack; taskid = emu->cur_ev->payload.i32[0]; HASH_FIND_INT(emu->cur_proc->tasks, &taskid, task); @@ -194,14 +198,12 @@ pre_task_resume(struct ovni_emu *emu) if(emu->cur_thread->state != TH_ST_RUNNING) die("thread is not running\n"); - if(emu->cur_thread->task != task) + if(top != task) die("thread has assigned a different task\n"); if(emu->cur_thread != task->thread) die("task is assigned to a different thread\n"); - emu->cur_thread->running_task = task; - task->state = TASK_ST_RUNNING; dbg("task id=%d resumes\n", task->id); @@ -211,9 +213,10 @@ pre_task_resume(struct ovni_emu *emu) static void pre_task_end(struct ovni_emu *emu) { - struct nosv_task *task; + struct nosv_task *task, *top; int taskid; + top = emu->cur_thread->task_stack; taskid = emu->cur_ev->payload.i32[0]; HASH_FIND_INT(emu->cur_proc->tasks, &taskid, task); @@ -227,7 +230,7 @@ pre_task_end(struct ovni_emu *emu) if(emu->cur_thread->state != TH_ST_RUNNING) die("thread is not running\n"); - if(emu->cur_thread->task != task) + if(top != task) die("thread has assigned a different task\n"); if(emu->cur_thread != task->thread) @@ -235,8 +238,8 @@ pre_task_end(struct ovni_emu *emu) task->state = TASK_ST_DEAD; task->thread = NULL; - DL_DELETE(emu->cur_thread->task, task); - emu->cur_thread->running_task = emu->cur_thread->task; + + DL_DELETE(emu->cur_thread->task_stack, task); dbg("task id=%d ends\n", task->id); } @@ -320,7 +323,7 @@ pre_task(struct ovni_emu *emu) { struct nosv_task *prev_task, *next_task; - prev_task = emu->cur_thread->running_task; + prev_task = emu->cur_thread->task_stack; switch(emu->cur_ev->header.value) { @@ -333,7 +336,7 @@ pre_task(struct ovni_emu *emu) abort(); } - next_task = emu->cur_thread->running_task; + next_task = emu->cur_thread->task_stack; /* Unless we're creating a task, register the switch */ if(emu->cur_ev->header.value != 'c')