From 45a6fdb04f3bf605eb4280473dd22db041ece6a7 Mon Sep 17 00:00:00 2001
From: xengineering <me@xengineering.eu>
Date: Sun, 26 Sep 2021 16:09:46 +0200
Subject: Remove startup.c and switch to libopencm3's Linker Script

---
 .gitignore          |  1 -
 Makefile            |  5 +----
 ld/stm32f103c8t6.ld | 35 ++++++-----------------------------
 src/startup.c       | 50 --------------------------------------------------
 4 files changed, 7 insertions(+), 84 deletions(-)
 delete mode 100644 src/startup.c

diff --git a/.gitignore b/.gitignore
index 8765efc..15a4222 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,2 @@
 docs
-baremetal
 build
diff --git a/Makefile b/Makefile
index 0b7e9c0..3a2f096 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,4 @@
 
-OBJS = main.o startup.o
-
 # tools
 PREFIX     ?= arm-none-eabi
 CC          = $(PREFIX)-gcc
@@ -10,8 +8,7 @@ OBJCOPY     = $(PREFIX)-objcopy
 all: deps/libopencm3/lib/libopencm3_stm32f1.a
 	mkdir build
 	$(CC) -O0 -c -g -DSTM32F1 -Ideps/libopencm3/include -mcpu=cortex-m3 -mthumb -o build/main.o src/main.c
-	$(CC) -O0 -c -g -DSTM32F1 -Ideps/libopencm3/include -mcpu=cortex-m3 -mthumb -o build/startup.o src/startup.c
-	$(LD) --static -nostartfiles -mcpu=cortex-m3 -mthumb -msoft-float -Tld/stm32f103c8t6.ld -Ldeps/libopencm3/lib build/startup.o build/main.o -lopencm3_stm32f1 -o build/ledcontrol.elf
+	$(LD) --static -nostartfiles -mcpu=cortex-m3 -mthumb -msoft-float -Tld/stm32f103c8t6.ld -Ldeps/libopencm3/lib build/main.o -lopencm3_stm32f1 -o build/ledcontrol.elf
 	$(OBJCOPY) -O binary build/ledcontrol.elf build/ledcontrol.bin
 
 deps/libopencm3/lib/libopencm3_stm32f1.a:
diff --git a/ld/stm32f103c8t6.ld b/ld/stm32f103c8t6.ld
index 9f74206..db01550 100644
--- a/ld/stm32f103c8t6.ld
+++ b/ld/stm32f103c8t6.ld
@@ -1,32 +1,9 @@
-SECTIONS
-{
-    .  = 0x0;         /* From 0x00000000 */
-
-    .text : 
-    {
-        *(vectors)    /* Vector table */
-        *(.text)      /* Program code */
-    }
-    .rodata : 
-    {
-        *(.rodata)    /* Read only data */
-    }
-    _DATA_ROM_START = .;
-
-    .  = 0x20000000;  /* From 0x20000000 */      
 
-    _DATA_RAM_START = .;
-    .data : AT(_DATA_ROM_START) 
-    {
-        *(.data)      /* Data memory */
-    }
-    _DATA_RAM_END = .;
-
-    _BSS_START = .;   /* Indicates where BSS section starts in RAM */
-    .bss :
-    {
-        *(.bss)       /* Zero-filled run time allocate data memory */
-    }
-    _BSS_END = .;     /* Indicates where BSS section ends in RAM */
+MEMORY
+{
+	rom (rx) : ORIGIN = 0x08000000, LENGTH = 64K
+	ram (rwx) : ORIGIN = 0x20000000, LENGTH = 20K
 }
 
+INCLUDE cortex-m-generic.ld
+
diff --git a/src/startup.c b/src/startup.c
deleted file mode 100644
index b71a805..0000000
--- a/src/startup.c
+++ /dev/null
@@ -1,50 +0,0 @@
-
-
-#define STACK_TOP 0x20005000
-
-
-extern unsigned int _BSS_START;
-extern unsigned int _BSS_END;
-extern unsigned int _DATA_ROM_START;
-extern unsigned int _DATA_RAM_START;
-extern unsigned int _DATA_RAM_END;
-
-void startup();
-void main();
-
-// Define the vector table
-unsigned int * myvectors[2] 
-__attribute__ ((section("vectors")))= {
-    (unsigned int *)    STACK_TOP,  // stack pointer
-    (unsigned int *)    startup     // code entry point
-};
-
-void startup()
-{
-    /* Set memory in bss segment to zeros */
-    unsigned int * bss_start_p = &_BSS_START; 
-    unsigned int * bss_end_p = &_BSS_END;
-
-    while(bss_start_p != bss_end_p)
-    {
-        *bss_start_p = 0;
-        bss_start_p++;
-    }
-
-    /* Copy memory in data segment from its position
-     * in the flash image to its position in the
-     * read/write memory */
-    unsigned int * data_rom_start_p = &_DATA_ROM_START;
-    unsigned int * data_ram_start_p = &_DATA_RAM_START;
-    unsigned int * data_ram_end_p = &_DATA_RAM_END;
-
-    while(data_ram_start_p != data_ram_end_p)
-    {
-        *data_ram_start_p = *data_rom_start_p;
-        data_ram_start_p++;
-        data_rom_start_p++;
-    }
-
-    /* Now we are ready to start the main function */
-    main();
-}
-- 
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