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#include "panic.h"
#include "task.h"
#include "paging.h"
struct tss {
struct tss *prev;
uint32_t esp0;
uint32_t ss0;
uint32_t esp1;
uint32_t ss1;
uint32_t esp2;
uint32_t ss2;
uint32_t cr3;
uint32_t eip;
uint32_t eflags;
uint32_t eax;
uint32_t ecx;
uint32_t edx;
uint32_t ebx;
uint32_t esp;
uint32_t ebp;
uint32_t esi;
uint32_t edi;
uint32_t es;
uint32_t cs;
uint32_t ss;
uint32_t ds;
uint32_t fs;
uint32_t gs;
uint32_t ldt;
uint16_t trap;
uint16_t iomp;
} __attribute__ ((packed));
#define TSS ((struct tss *)0x00004f98)
#define MAX_TASKS 64
struct task_state tasks[MAX_TASKS];
struct task_state *active_task;
void init_tasks() {
active_task = tasks;
for (uint8_t i = 0; i < MAX_TASKS; ++i)
tasks[i].page_directory = 0;
TSS->ss0 = 0x18;
TSS->esp0 = 0x00040000;
//TSS->cs = 0x13;
//TSS->ds = 0x1b;
//TSS->ss = 0x1b;
TSS->iomp = sizeof(struct tss);
asm volatile (
"mov $0x08, %%ax\n"
"ltr %%ax"
: : : "ax");
}
void new_task(struct task_state state) {
for (uint8_t n = 0; n < MAX_TASKS; ++n)
if (!tasks[n].page_directory) {
tasks[n] = state;
return;
}
panic("Maximum number of tasks reached.");
}
void advance_active_task() {
struct task_state *prev_task = active_task;
do {
if (++active_task == tasks + MAX_TASKS)
active_task = tasks;
if (active_task == prev_task) {
logsz("No active tasks.\nHalting.");
while (1)
asm ("hlt");
}
}
while (!active_task->page_directory);
}
void delete_task(struct task_state *state) {
free_task_pd(state->page_directory);
state->page_directory = 0;
}
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