System Calls cleanup, multiple Processes and context switch

diff --git a/README.md b/README.md
index 113cf6a..e9473b8 100644 (file)
--- a/README.md
+++ b/README.md
@@ -29,14 +29,17 @@ port this code to any Cortex M0/M3/M4/M7 board.
        * Temperature sensor: drivers/tsensor.c [COMPLETED]
        * OLED display [PLANNED]
        * Joystick: drivers/mk450_joystick.c [COMPLETED]
-       * TFT Screen: drivers/st7735s.c, include/libs/fonts/wogfont.h [IN PROGRESS]
+       * TFT Screen: drivers/st7735s.c, include/libs/fonts/wogfont.h [COMPLETED]
 * Memory Management [IN PROGRESS] -- FILE: lib/pool.c
-* User Mode [PLANNED]
-* System Call PendV implementation [PLANNED]
+* Kernel heap [COMPLETED] -- FILE: heap.c
+* User Mode Switch [IN PROGRESS]
+* System Calls [IN PROGRESS] -- FILE: syscall.c lib/syscall.c
+* Scheduler based on PendSV system call [IN PROGRESS]   
 * Stack trace debug [IN PROGRESS]
-* Memory Protection Unit [PLANNED]
+* Memory Protection Unit [SUSPENDED] (STM32F103 board has no MPU)
 * Loadable programs from EEPROM [PLANNED]
-* Multiple processes and scheduling [PLANNED]
+* Multiple processes [IN PROGRESS] -- FILES: process.h, main.c 
+* Driver "abstraction" [PLANNED] 
 
 ## SCREENSHOTS
 Here are some screenshots that shows the terminal just after booting:

diff --git a/lib/syscall.c b/lib/syscall.c
index d844b43..34401c5 100644 (file)
--- a/lib/syscall.c
+++ b/lib/syscall.c
@@ -5,7 +5,7 @@
  * Initial version 
  * 
  * $DESCRIPTION$
- * System calls for user functions
+ * System calls for various user functions
  *
  */
 
@@ -18,11 +18,11 @@
 /* Arguments are placed in r0, r1, r2 by convention
  * And "parsed" to the the kernel
  * Right after the svc call, r0 contains status
- * of call (ie. OK, NOTOK */
+ * of call (ie. OK, SYSERR) */
 
 int theos_uptime() {
 
-       asm volatile("svc 6");
+       asm volatile("svc 7");
        int ret;
        asm volatile("mov %0, r0" : "=r" (ret));        
        return ret;

diff --git a/main.c b/main.c
index ac01416..4eb79f9 100644 (file)
--- a/main.c
+++ b/main.c
@@ -23,6 +23,7 @@
 #include <lib/stdio.h>
 #include <lib/string.h>
 #include <lib/tinyprintf.h>
+#include <lib/syscall.h>
 
 #include <drivers/uart.h>
 #include <drivers/led.h>
@@ -32,52 +33,18 @@
 //#include <drivers/mk450_joystick.h>
 #include <drivers/st7735s.h>
 
-#include <lib/syscall.h>
-
 
+/* Example of multitasking */
 process_t p1;
 process_t p2;
 
 uint32_t stackp1[500];
 uint32_t stackp2[500];
 
-extern int count;
-
-void switch_usermode() {
-
-       // user mode 
-       //asm volatile ("mov r0, 0x1" "\n\t" 
-       //"msr control, r0" "\n\t"
-       //"isb" "\n\t"); 
-
-       // system init call
-
-}
-
-void process1(void) {
-       
-       while(1) {
-               //uint32_t control = 0xFFFFFFFF;
-               printf("process 1\n");
-               //asm volatile("msr control, %0" "\n\t"
-               //             "dsb" : : "r" (control));
-               //printf("control: %x", control);       
-               //for(;;);
-               _block(100);
-               theos_switch(&p1, &p2);
-       }
+void process1(void);
+void process2(void);
 
-}
-void process2(void) {
-       while(1) {
-               printf("process 2\n");
-               _block(100);
-               theos_switch(&p2, &p1);
-       }
-       
-}
 
-int test_data_segment = 99;
 
 void main()
 {
@@ -116,38 +83,26 @@ void main()
        /* Real time clock */
        rtc_init();
 
-
-//     printf("press any key to start\n");
-//     asm volatile ("cpsid f"); // doesn't work in qemu
-
+       /* Initialize SVC handler for system calls*/
        syscall_init();
 
-       //int ret;
-       //ret = theos_test(0x1, 0x2, 0x3);
-       //ret = theos_uptime();
-
-       //printf("ret: %d\n", ret);
+       /* System call test */
+       int uptime = theos_uptime();
+       printf("UPTIME: %d\n", uptime);
 
-       int size_stack = sizeof(stackp1);
-       
-       p1.stackptr = ((unsigned int) stackp1) + size_stack - 0x1C;
-       p1.stackptr[6] = (uint32_t) process1;
-       p1.stackptr[7] = 0x01000000;
-       p2.stackptr = ((unsigned int) stackp2) + size_stack - 0x1C;
-       p2.stackptr[6] = (uint32_t) process2;
-       p2.stackptr[7] = 0x01000000;
-       
-       theos_init(&p1);
+       /* Multi processes test */
+//     int size_stack = sizeof(stackp1);
+//     p1.stackptr = ((unsigned int) stackp1) + size_stack - 0x1C;
+//     p1.stackptr[6] = (uint32_t) process1;
+//     p1.stackptr[7] = 0x01000000;
+//     p2.stackptr = ((unsigned int) stackp2) + size_stack - 0x1C;
+//     p2.stackptr[6] = (uint32_t) process2;
+//     p2.stackptr[7] = 0x01000000;
+//     theos_init(&p1);
 
        /* Cortex M* integrated systick, can be replaced
         * by the more accurate RTC. */
-       
-//     systick_init();
-
-       //      switch_usermode();      
-
-       //printf("without system call");        
-//     theos_test(0xA1, 0xA2);
+       //systick_init();
 
        /* Eeprom Driver
        eeprom_at24c_init();
@@ -169,7 +124,6 @@ void main()
        /* ADC Joystick module */
        // mk450_init();        
 
-
        /* Start up terminal */
        terminal();
        
@@ -178,3 +132,21 @@ void main()
 
        }
 }
+
+void process1(void) {
+       
+       while(1) {
+               printf("process 1\n");
+               _block(0xFFFFF);
+               theos_switch(&p1, &p2);
+       }
+
+}
+void process2(void) {
+       while(1) {
+               printf("process 2\n");
+               _block(0xFFFFF);
+               theos_switch(&p2, &p1);
+       }
+       
+}

diff --git a/syscall.c b/syscall.c
index ba0dc9a..2250009 100644 (file)
--- a/syscall.c
+++ b/syscall.c
@@ -10,13 +10,14 @@
  * | SYSTEM CALL       | #     |
  * |--------------------|-------|
  * | THEOS_INIT                | 1     |
- * | THEOS_DESTROY     | 2     |
- * | THEOS_RESCHED     | 3     |
- * | THEOS_GETC                | 4     |
- * | THEOS_CPUTS       | 5     |
- * | THEOS_UPTIME      | 6     |
- * | THEOS_OMNIGOD     | 7     |
- * | THEOS_TIME                | 8     |
+ * | THEOS_CREATE      | 2     |
+ * | THEOS_DESTROY     | 3     |
+ * | THEOS_SWITCH      | 4     |
+ * | THEOS_GETC                | 5     |
+ * | THEOS_CPUTS       | 6     |
+ * | THEOS_UPTIME      | 7     |
+ * | THEOS_OMNIGOD     | 8     |
+ * | THEOS_TIME                | 9     |
  * | THEOS_MAGIC       | 99    |
  * |----------------------------|
  *
@@ -70,10 +71,9 @@ int sys_switch(process_t * currp, process_t * newp) {
        uint32_t chk_stackptr;
        asm volatile("mrs %0, psp" : "=r" (chk_stackptr));
        //asm volatile("isb");
-       printf("OLD: %x\n", currp->stackptr);
-       printf("NEW: %x\n", newp->stackptr);
-       printf("CHK: %x\n", chk_stackptr);
-       //for(;;);
+       //printf("OLD: %x\n", currp->stackptr);
+       //printf("NEW: %x\n", newp->stackptr);
+       //printf("CHK: %x\n", chk_stackptr);
 
        return 0;
 

diff --git a/systick.c b/systick.c
index 2c49820..f459512 100644 (file)
--- a/systick.c
+++ b/systick.c
@@ -21,31 +21,6 @@
 #include <lib/regfunc.h>
 #include <lib/tinyprintf.h>
 
-#define NUMB_TASKS 3
-
-int count;
-int next_task;
-int curr_task;
-uint32_t currentp;
-uint32_t nextp;
-
-//struct proces {
-//     int32_t nr;
-//     uint32_t *stack_ptr;
-//     uint32_t mask;
-//};
-//
-//struct proces p1, p2, p3;
-//
-//
-//     uint32_t oldpsp;
-//     uint32_t newpsp;
-//
-//uint32_t task0_stack[50];
-//uint32_t task1_stack[50];
-//uint32_t task2_stack[50];
-//uint32_t PSP_array[3];
-
 struct interrupt_frame {
 
         uint32_t r0; // N-32
@@ -61,25 +36,7 @@ struct interrupt_frame {
 //__attribute__ ((interrupt))
 void * systick_handler(/* struct interrupt_frame * frame */) {
 
-       //printf("Ticking...\n");
-       //printf("Current task: %d", curr_task);
-       //count++;
-
-
-
-
-       //switch(curr_task) {
-       //      case(0): next_task = 1; break;
-       //      case(1): next_task = 2; break;
-       //      case(2): next_task = 0; break;
-       //      default: next_task = 0; break;
-       //} 
-
-       //if (curr_task != next_task) {
-       
-               
-       
-       //} 
+       printf("Ticking...\n");
 
 }
 
@@ -114,10 +71,6 @@ uint32_t set_psp(uint32_t stackie) {
 
 void systick_init() {
 
-//     count = 0;
-//     curr_task = 0;
-//     next_task = 1;
-
        /* Every time the counter counts down to zero
         * a systick exception is invoked. Systick has
         * exception number 15. in the vector table  */
@@ -137,56 +90,4 @@ void systick_init() {
        rsetbit(STK_CTRL, 0);
        rsetbit(STK_CTRL, 1);
 
-//     extern void task0(void), task1(void), task2(void);
-//
-//     int size_stack = sizeof(task0_stack);
-//     
-//     p1.stack_ptr  = ((unsigned int) task0_stack) + size_stack - 0x1C;
-//     p1.stack_ptr[6] = (uint32_t) task0;
-//     p1.stack_ptr[7] = 0x01000000;
-//     p2.stack_ptr  = ((unsigned int) task0_stack) + size_stack - 0x1C;
-//     p2.stack_ptr[6] = (uint32_t) task1;
-//     p2.stack_ptr[7] = 0x01000000;
-//     p3.stack_ptr  = ((unsigned int) task0_stack) + size_stack - 0x1C;
-//     p3.stack_ptr[6] = (uint32_t) task2;
-//     p3.stack_ptr[7] = 0x01000000;
-//
-//     set_psp(p1.stack_ptr[-7]);
-//
-//     for(;;);        
-
-       /* Initialize processes */
-       //PSP_array[0] = ((unsigned int) task0_stack) + sizeof(task0_stack) - 32*4;
-       //HW_ADDR(PSP_array[0] + 0x18) = (unsigned long) task0;
-        //HW_ADDR(PSP_array[0] + 0x1C) = 0x01000000;   
-       //PSP_array[1] = ((unsigned int) task1_stack) + sizeof(task1_stack) - 32*4;
-       //HW_ADDR(PSP_array[1] + 0x18) = (unsigned long) task1;
-        //HW_ADDR(PSP_array[1] + 0x1C) = 0x01000000;   
-       //PSP_array[2] = ((unsigned int) task2_stack) + sizeof(task2_stack) - 32*4;
-       //HW_ADDR(PSP_array[2] + 0x18) = (unsigned long) task2;
-        //HW_ADDR(PSP_array[2] + 0x1C) = 0x01000000;   
-
-       //extern void pendsv_handler;
-
-       ivt_set_gate(14, pendsv_handler_c, 0);
-
-       //set_psp((PSP_array[curr_task] + 32*4 ));
-       
-       //int startpsp = PSP_array[curr_task] + 16*4;
-
-       //asm volatile ("msr psp, %0" : : "r" (startpsp));
-       
-       
-       //asm volatile ("mov r0, 0x3" "\n\t" 
-       //"msr control, r0" "\n\t"
-       //"isb" "\n\t"); 
-
-       //for(;;);
-
-       //set current PSP
-       //printf("0: %x\n", PSP_array[0]);
-       //printf("1: %x", PSP_array[0]);
-
-       //task0();
-
 }