From 943e2bfa931a0d9786a9bad07f7762b753d7a1a9 Mon Sep 17 00:00:00 2001
From: Kyle Isom <kyle@imap.cc>
Date: Mon, 12 Mar 2018 22:16:18 -0700
Subject: [PATCH] blue-pill: fix linker scripts and asm led turnon

---
 blue-pill/asm-blink/Makefile    | 70 +++++++++++++++++++++++++++++++++
 blue-pill/asm-blink/blink.S     | 43 ++++++++++++++++++++
 blue-pill/asm-blink/bluepill.ld | 18 +++++++++
 blue-pill/draugr/startup.s      |  2 +
 blue-pill/draugr/stm32f103.ld   | 13 ++++--
 5 files changed, 143 insertions(+), 3 deletions(-)
 create mode 100644 blue-pill/asm-blink/Makefile
 create mode 100644 blue-pill/asm-blink/blink.S
 create mode 100644 blue-pill/asm-blink/bluepill.ld

diff --git a/blue-pill/asm-blink/Makefile b/blue-pill/asm-blink/Makefile
new file mode 100644
index 0000000..1c7ba4b
--- /dev/null
+++ b/blue-pill/asm-blink/Makefile
@@ -0,0 +1,70 @@
+# configurables
+OBJS :=		
+TARGET :=	blink
+OBJS +=		$(TARGET).o
+
+# targets
+ELF :=		$(TARGET).elf
+BIN :=		$(TARGET).bin
+
+# toolchain setup
+ARMTC :=	arm-none-eabi
+CC :=		$(ARMTC)-gcc
+LD :=		$(ARMTC)-gcc
+AS :=		$(ARMTC)-as
+ARMSIZE :=	$(ARMTC)-size
+OBJCOPY :=	$(ARMTC)-objcopy
+PAGER ?=	less
+
+# compiler options
+CPUFLAGS :=	-mcpu=cortex-m3 -mthumb -std=c99
+CFLAGS :=	-Wall -Wextra -Os -MD $(CPUFLAGS) -g
+LDFLAGS :=	$(CPUFLAGS) -nostartfiles -Wl,-T,bluepill.ld
+LDLIBS :=	-lc -lnosys
+
+# programmer options
+STARTMEM :=	0x8000000
+
+# targets
+
+.PHONY: all
+all: $(BIN)
+
+$(ELF): $(OBJS)
+	$(CC) $(LDFLAGS) -o $@ $(OBJS) $(LDLIBS)
+	$(ARMSIZE) $@
+
+.PHONY: strip
+strip: $(ELF)
+	$(ARMTC)-strip $(ELF)
+	$(ARMSIZE) $(ELF)
+
+$(BIN): $(ELF)
+	$(OBJCOPY) -O binary $< $@
+
+.PHONY: flash
+flash: $(BIN)
+	st-flash write $(BIN) $(STARTMEM)
+
+.PHONY: erase
+erase:
+	st-flash erase
+
+.PHONY: reset
+reset:
+	st-flash reset
+
+.PHONY: install
+install: erase flash reset
+
+.PHONY: clean
+clean:
+	rm -f *.o *.bin *.elf *.d *.map
+
+.PHONY: disass
+disass: $(ELF)
+	$(ARMTC)-objdump -D $(ELF) | $(PAGER)
+
+.PHONY: dump
+dump: $(ELF)
+	$(ARMTC)-objcopy -D $(ELF) > $(TARGET).dump
diff --git a/blue-pill/asm-blink/blink.S b/blue-pill/asm-blink/blink.S
new file mode 100644
index 0000000..b4d0955
--- /dev/null
+++ b/blue-pill/asm-blink/blink.S
@@ -0,0 +1,43 @@
+.syntax unified
+.cpu cortex-m3
+.thumb
+
+.section .text
+.global	vectors
+vectors:
+.align	2
+.word	0
+.word	_start
+
+.thumb_func
+.global	_start
+_start:
+	/* enable port C clock */
+	ldr	r0,	=0x40021000
+	ldr	r1,	[r0, #0x18]
+	mov	r2,	#5
+	orr	r1,	r2
+	str	r1,	[r0, #0x18]
+
+	/*
+	 * enable output mode at a max of 2 MHz.
+	 * note that the default is a general purpose output push-pull,
+	 * which is what it should be.
+	 */
+	ldr	r0,	=0x40011000
+	ldr	r1,	[r0, #0x04]
+	mov	r2,	#0x02
+	lsl	r2,	#0x14
+	orr	r1,	r2
+	str	r1,	[r0, #0x04]
+
+	/* write LED pin (PC13) */
+	ldr	r0,	=0x40011000
+	ldr	r1,	[r0, #0x10]
+	mov	r2,	#0x01
+	lsl	r2,	#0x0d
+	lsl	r2,	#0x10
+	orr	r1,	r2
+	str	r1,	[r0, #0x10]
+
+hang:	bl .
diff --git a/blue-pill/asm-blink/bluepill.ld b/blue-pill/asm-blink/bluepill.ld
new file mode 100644
index 0000000..ee4d607
--- /dev/null
+++ b/blue-pill/asm-blink/bluepill.ld
@@ -0,0 +1,18 @@
+MEMORY
+{
+    flash (rx) : ORIGIN = 0x08000000, LENGTH = 64K
+    sram (rwx) : ORIGIN = 0x20000000, LENGTH = 20K
+}
+
+EXTERN(vectors);
+ENTRY(_start);
+
+SECTIONS
+{
+	.text : {
+		*(.vectors*)
+ 		*(.text*)
+		. = ALIGN(4);
+	} > flash
+	.bss  : { *(.bss*) } > sram
+}
diff --git a/blue-pill/draugr/startup.s b/blue-pill/draugr/startup.s
index 5c55a35..f3f4e33 100644
--- a/blue-pill/draugr/startup.s
+++ b/blue-pill/draugr/startup.s
@@ -9,6 +9,8 @@
 .cpu cortex-m3
 .thumb
 
+.section	.text
+.global vectors
 vectors:
 .align	2
 .long	0x20005000		/* stack pointer points to top of SRAM */
diff --git a/blue-pill/draugr/stm32f103.ld b/blue-pill/draugr/stm32f103.ld
index 9d7fa01..d00ebd2 100644
--- a/blue-pill/draugr/stm32f103.ld
+++ b/blue-pill/draugr/stm32f103.ld
@@ -1,11 +1,18 @@
 MEMORY
 {
-    flash (rx) : ORIGIN = 0x00000000, LENGTH = 128K
+    flash (rx) : ORIGIN = 0x08000000, LENGTH = 64K
     sram (rwx) : ORIGIN = 0x20000000, LENGTH = 20K
 }
 
+EXTERN(vectors);
+ENTRY(reset_handler);
+
 SECTIONS
 {
-   .text : { *(.text*) } > flash
-   .bss  : { *(.bss*) } > sram
+	.text : {
+		*(.vectors*)
+ 		*(.text*)
+		. = ALIGN(4);
+	} > flash
+	.bss  : { *(.bss*) } > sram
 }