From 836a9d3addf107e10ee464600ecf2550e25012bc Mon Sep 17 00:00:00 2001
From: imi415 <imi415.public@gmail.com>
Date: Wed, 10 Aug 2022 01:21:53 +0800
Subject: [PATCH] Newlib _exit will not be executed, replaced by a dead loop.

---
 CMakeLists.txt      |  2 +-
 src/main.c          | 41 +++++++++++++++++++++++++++++++++++++++--
 src/stx7105_utils.c |  6 +++---
 startup_stx7105.S   | 13 +++++++------
 4 files changed, 50 insertions(+), 12 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index a95f8de..77f0950 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -31,7 +31,7 @@ set(CMAKE_EXE_LINKER_FLAGS_RELEASE "-flto")
 
 set(CMAKE_C_FLAGS          "${TARGET_FLAGS_HARDWARE} -Wall -ffunction-sections -fdata-sections")
 set(CMAKE_CXX_FLAGS        "${TARGET_FLAGS_HARDWARE} -Wall -ffunction-sections -fdata-sections")
-set(CMAKE_EXE_LINKER_FLAGS "${TARGET_FLAGS_HARDWARE} -Wall -lc -lm -nostartfiles -Wl,--print-memory-usage -Wl,--gc-sections")
+set(CMAKE_EXE_LINKER_FLAGS "${TARGET_FLAGS_HARDWARE} -Wall -specs=nosys.specs -lc -lm -nostartfiles -Wl,--print-memory-usage -Wl,--gc-sections")
 
 add_compile_definitions(${TARGET_DEFS})
 include_directories(${TARGET_INCLUDES})
diff --git a/src/main.c b/src/main.c
index 58982f6..0e5d0cb 100644
--- a/src/main.c
+++ b/src/main.c
@@ -16,6 +16,9 @@
 #define SYSTEM_CONFIG34 (0xFE001188U) /* PIO4 */
 #define SYSTEM_CONFIG7  (0xFE00111CU) /* RXSEL */
 
+#define MEMTEST_START 0x80010000
+#define MEMTEST_END   0x8FFE0000
+
 void uart_init(void) {
     PIO4->CLR_PC0 = 1U; /* PC = 110, AFOUT, PP */
     PIO4->SET_PC1 = 1U;
@@ -31,6 +34,28 @@ void uart_init(void) {
     CONSOLE_ASC->CTRL     = 0x1589UL; /* 8N1, RX enable, FIFO enable, Baud mode 1 */
 }
 
+static void memory_test(void) {
+    for (uint32_t i = MEMTEST_START; i < MEMTEST_END; i += 4) {
+        *(uint32_t *)i = i;
+
+        if (i % 0x10000 == 0U) {
+            printf("Write to 0x%08x...\r\n", i);
+        }
+    }
+
+    for (uint32_t i = MEMTEST_START; i < MEMTEST_END; i += 4) {
+        if (*(uint32_t *)i != i) {
+            printf("Read back error at 0x%08x\r\n", i);
+
+            return;
+        }
+
+        if (i % 0x10000 == 0U) {
+            printf("Read from 0x%08x...\r\n", i);
+        }
+    }
+}
+
 int main(void) {
     init_led(LED_RED_GPIO, LED_RED_PIN, 0U);
     init_led(LED_BLUE_GPIO, LED_BLUE_PIN, 0U);
@@ -39,10 +64,22 @@ int main(void) {
 
     printf("Hello world\r\n");
 
+    printf("Size of int: %d\r\n", sizeof(int));
+    printf("Size of short: %d\r\n", sizeof(short));
+    printf("Size of char: %d\r\n", sizeof(char));
+    printf("Size of long: %d\r\n", sizeof(long));
+    printf("Size of pointer: %d\r\n", sizeof(uint8_t *));
+    printf("Size of uint8_t: %d\r\n", sizeof(uint8_t));
+    printf("Size of uint16_t: %d\r\n", sizeof(uint16_t));
+    printf("Size of uint32_t: %d\r\n", sizeof(uint32_t));
+
+    delay_ms(5000);
+
+    memory_test();
+
     for (;;) {
         set_led(LED_BLUE_GPIO, LED_BLUE_PIN, 1U);
         delay_ms(500);
-        printf("Hello ?\r\n");
         set_led(LED_BLUE_GPIO, LED_BLUE_PIN, 0U);
         delay_ms(500);
     }
@@ -51,7 +88,7 @@ int main(void) {
 }
 
 void _putchar(char ch) {
-    while(CONSOLE_ASC->STA & 1 << 9U) {
+    while (CONSOLE_ASC->STA & 1 << 9U) {
         // wait for TX FIFO slot.
     }
     CONSOLE_ASC->TX_BUF = ch;
diff --git a/src/stx7105_utils.c b/src/stx7105_utils.c
index 6efa2eb..271c25b 100644
--- a/src/stx7105_utils.c
+++ b/src/stx7105_utils.c
@@ -24,10 +24,10 @@ void set_led(PIO_TypeDef *gpiox, uint8_t pin, uint8_t val) {
 
 void delay_ms(uint32_t msec) {
     /* Initialize TMU and count to zero */
-    /* TMU clock is from Peripheral clock, approx. 66MHz */
-    /* Prescale to 66kHz for convenience (TMUs can only divide by max. 1024) */
+    /* TMU clock is from Peripheral clock, approx. 100MHz */
+    /* Prescale to 100kHz for convenience (TMUs can only divide by max. 1024) */
 
-    uint32_t reload_value = msec * 66 - 1;
+    uint32_t reload_value = msec * 100 - 1;
 
     TMU->TSTR &= ~TMU_TSTR_STR0_Msk;       /* Stop counter */
     TMU->TCR0  = 0x04U | TMU_TCR_UNIE_Msk; /* 1024 prescale, enable interrupt */
diff --git a/startup_stx7105.S b/startup_stx7105.S
index 686fec1..ae1ab94 100644
--- a/startup_stx7105.S
+++ b/startup_stx7105.S
@@ -63,10 +63,11 @@ _main_entry:
     jsr @r0
     or r0, r0
 
-    mov r0, r4
-    mov.l _exit_k, r0
-    jsr @r0
-    or r0, r0
+    mov.l _exit_loop_k, r0
+_exit_loop:
+    sleep
+    jmp @r0
+    nop
 
     .balign 4
 /* libc FPU routine */
@@ -88,8 +89,8 @@ _end_k:
 /* Function pointers */
 _main_k:
     .long _main /* Same address as main */
-_exit_k:
-    .long _exit
+_exit_loop_k:
+    .long _exit_loop
 _exc_base_k:
     .long _exc_base
 _exc_imask_k: