basic memory management and uart wait fix

diff --git a/Makefile b/Makefile
index 9f7f517..9eba3b4 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -4,7 +4,7 @@ AR=$(TOOLROOT)/arm-none-eabi-ar
 AS=arm-none-eabi-as
 MKIMG=arm-none-eabi-objcopy
 
-LDFLAGS+= -mthumb -mcpu=cortex-m3 
+LDFLAGS+= -mthumb -mcpu=cortex-m0 
 CFLAGS+= -mcpu=cortex-m3 -mthumb -g 
 
 as: 

diff --git a/include/mmap.h b/include/mmap.h
index 1aba65b..6fa4adc 100644 (file)
--- a/include/mmap.h
+++ b/include/mmap.h
@@ -7,8 +7,8 @@
  * */
 
 
-#define BSS_BASE ((volatile uint32_t)(0x20000000));
-#define MEM_SIZE 512000;
+#define BSS_BASE ((volatile uint32_t *)(0x20000800)) //TODO: .data flexible siz
+#define TOTAL_MEM_SIZE 64000;
 
 /* SYSTEM INFO AND DEBUG */
 #define MCU_ID ((volatile uint32_t*)( 0xE0042000)) 

diff --git a/include/stm32.h b/include/stm32.h
index 37f039f..4f52257 100644 (file)
--- a/include/stm32.h
+++ b/include/stm32.h
@@ -28,4 +28,10 @@ extern void sysinfo();
 /* LIB.C */
 extern void addrtohex(const uint32_t);
 
+/* MM.C */
+extern void mm_init();
+extern void * mm_alloc(size_t);
+extern void free(void *);
+extern void test_memory(uint32_t *);
+
 #endif

diff --git a/lib.c b/lib.c
index 62c56e8..69bb12d 100644 (file)
--- a/lib.c
+++ b/lib.c
@@ -9,13 +9,12 @@
 
 char hexbuf[8] = {'0', '0','0', '0','0', '0','0', '0'};
 
-void addrtohex(const uint32_t addr) {
+void addrtohex(uint32_t addr) {
        char tmpbuf[6] = {'A', 'B', 'C', 'D', 'E', 'F'};
        memset(&hexbuf, 0, sizeof(uint32_t) * 8);
-       uint32_t tmp = addr;
 
        for (int i = 0; i < 8 ; i++) {
-               tmp = addr;
+               uint32_t tmp = addr;
                tmp = tmp >> (i * 4);
                tmp = tmp & 0xF;
                if ((tmp >= 0) && tmp < 10) {
@@ -27,20 +26,10 @@ void addrtohex(const uint32_t addr) {
        }
 
        uart_puts("ADDRESS: 0x");
-       for (int i = 7; i >= 0; i--) {
+        for (int i = 7; i >= 0; i--) {
                uart_putc(hexbuf[i]);
-       }
+       } 
+       //uart_puts(hexbuf);
        uart_putc('\n');
 }
 
-
-void *malloc(size_t size) {
-
-
-
-}
-
-void free(void * ptr) {
-
-
-}

diff --git a/link.ld b/link.ld
index d1a01dd..8301b2c 100644 (file)
--- a/link.ld
+++ b/link.ld
@@ -1,9 +1,9 @@
-/* 
- * MEMORY MAP
+/* */
+MEMORY
 {
        FLASH (xr) : ORIGIN = 0x08000000, LENGTH = 512K
        SRAM (xrw) : ORIGIN = 0x20000000, LENGTH = 64K
-} */
+} 
 
 ENTRY(_start) 
 
@@ -20,9 +20,9 @@ SECTIONS
        .data :  
        {
                *(.data)
-       }
+       } 
        .bss : ALIGN(256)
        {
                *(.bss)
-       }
+       } 
 }

diff --git a/main.c b/main.c
index 5b488cf..84496d5 100644 (file)
--- a/main.c
+++ b/main.c
@@ -49,8 +49,19 @@ void main()
        systick_init();
        uart_puts("LOADING SYSTEM 0.1 ...\n");
        sysinfo();
-       addrtohex((volatile uint32_t) 0x12345678 );
-       addrtohex((volatile uint32_t) *SCB_VTOR );
+       mm_init();
+
+       int * p2 = mm_alloc(200);
+       *p2 = 0x12345678;
+
+       test_memory(p2);
+
+       addrtohex(p2);
+       addrtohex(*p2);
+
+
+       //addrtohex((volatile uint32_t) 0x12345678 );
+       //addrtohex((volatile uint32_t) SCB_VTOR );
 
 //     asm("cpsie i"); // enable irq , cpsied f (disable faukts(
 

diff --git a/mm.c b/mm.c
index ba0cc2c..4f56459 100644 (file)
--- a/mm.c
+++ b/mm.c
@@ -4,18 +4,98 @@
 #include <stm32.h>
 #include <mmap.h>
 
-uint32_t free_base;
+/* TOTAL SRAM MEMORY: 64kB 
+ * 64 chunks of 1kB 
+ * 128 chunks of 512 bytes
+ * SIMPLE BITMAP IMPLEMENTATION
+ * */
+
+#define CHUNKS  128
+#define FREE   0x00
+#define ALLOC  0x01
+
+#define BASE 0x20000400
+
+#define SET_SIZE(s)    (s << 8)
+#define SET_FLAGS(f)   (f << 24)
+#define IS_ALLOC(c)    ((c >> 24) & 0x0F )
+#define PADDR(i)       (0x20000400 + (i * 0x200))
+#define I_OFFSET(p)     ((p  - 0x20000400))
+
+uint32_t chunk[CHUNKS];
+
+/* 
+ * | FLAGS | SIZE   | RESERVED |
+ * | 0x00  | 0x0000 | 0x00             |
+ *
+ * */
 
 
 void mm_init() {
 
-       free_base = MEM_SIZE;
+       // interrupt vector
+       chunk[0] = SET_SIZE(96) | SET_FLAGS(ALLOC); 
+
+       // test
+       /* uart_puts("ALLOC:\n");
+       int * p = mm_alloc(100);
+       *p = 0x12345678;
+
+       addrtohex(p);
+       addrtohex(*p);
+
+       uart_puts("FREE:\n");
+
+       int * p2 = mm_alloc(100);
+       *p2 = 0xFFFFAAAA;
+       addrtohex(p2);
+       addrtohex(*p2);
 
+       free(p);
+       free(p2); */
 }
 
-size_t mm_free() {
+ void test_memory(uint32_t * ptr) {
+
+       *ptr = 0xEEEEEEEE;
+       for (int i = 0; i < 100; i++) {
+               ptr++;
+               *ptr = 0xEEEEEEEE;
+       }
+
+} 
+
+
+void * mm_alloc(size_t size) { // in bytes
+
+       if (size > 512) {
+               uart_puts("SYSERROR: WE CAN'T ALLOCATE THAT MUCH!\n");
+               return NULL; 
+       }
+
+       /* check which chunk is free */
+       for (int i = 1; i < CHUNKS; i++) {
+               if (!IS_ALLOC(chunk[i])) {
+                       chunk[i] = SET_SIZE(size) | SET_FLAGS(ALLOC);
+                       return (void *) PADDR(i);
+               }
+       }
+       
+       uart_puts("SYSERROR: OUT OF MEMORY\n");
+       return NULL;
+}
+
+void free(void *ptr) {
+
+       uint32_t index = (uint32_t) I_OFFSET(ptr) / 0x200;
 
-       return MEM_SIZE; 
+       uint32_t tmp = chunk[index];
+       if (!IS_ALLOC(tmp))
+               uart_puts("SYSERROR: ALREADY FREED!\n");
 
+       else if(index < CHUNKS) {
+               chunk[index] = SET_FLAGS(FREE) | SET_SIZE(0);
+       }
+               
 }
 

diff --git a/start.asm b/start.asm
index 294a718..d8c7244 100644 (file)
--- a/start.asm
+++ b/start.asm
@@ -1,4 +1,4 @@
-       .equ STACK_TOP, 0x20000800
+       .equ STACK_TOP, 0x20008000 /* placed at 32kB, TODO: could place at top of SRAM? */
        .text
        .global _start
        .global reset, nmi, hardfault
@@ -34,7 +34,7 @@ stub:
        mov R1,#0
        udiv.w R2, R0, R1 */
 
-       .data
-       .word 'x'
+/*     .data
+       .word 'x' */
        .end
 

diff --git a/uart.c b/uart.c
index 93b2c91..a3905c4 100644 (file)
--- a/uart.c
+++ b/uart.c
@@ -43,6 +43,9 @@ void uart_init() {
 */
 }
 
+void wait() {
+       for (int i = 0; i < 100; i++);
+}
 
 extern void uart_putc(unsigned char ch) {
        
@@ -50,15 +53,16 @@ extern void uart_putc(unsigned char ch) {
                while (*USART1_SR & 0x0C) { } // transmit data register empty and complete
                *USART1_DR = 0x0D; // return line
        }
-       
-       while ((*USART1_SR & 0xFF) == 0x0C) {} // busy bit  
+
+
+       while (*USART1_SR & 0x0C) {} 
                *USART1_DR = ch;
 
-}
 
-void wait() {
-       for (int i = 0; i < 100; i++);
+       
+       wait();
 }
+
 extern void uart_puts(unsigned char *str)
 {
 
@@ -66,7 +70,6 @@ extern void uart_puts(unsigned char *str)
 
     for (i = 0; i < strlen(str); i++)
     {
-       wait();
         uart_putc(str[i]);
     }
 }