Makefile

@@ -1,26 +1,10 @@
 CROSS_COMPILE = arm-none-eabi-
-GCC_COMPILE_ARGS = -x assembler-with-cpp -c -O0 -g3 -mcpu=cortex-m4 -mthumb -Wall
 
-build: start.o lab1.o ldscript.ld
+build: start.S
-	$(CROSS_COMPILE)gcc start.o lab1.o \
+	$(CROSS_COMPILE)gcc -x assembler-with-cpp -c -O0 -g3 -mcpu=cortex-m4 -mthumb -Wall -o start.o start.S
-		-mcpu=cortex-m4 -mthumb -Wall \
+	$(CROSS_COMPILE)gcc start.o -mcpu=cortex-m4 -mthumb -Wall --specs=nosys.specs -nostdlib -lgcc -T./ldscript.ld -o start.elf
-		--specs=nosys.specs -nostdlib -lgcc -T./ldscript.ld \
-		-o start.elf
 	$(CROSS_COMPILE)objcopy -O binary -F elf32-littlearm start.elf start.bin
 
-start.o: start.S lab1_v2.bin
-	$(CROSS_COMPILE)gcc $(GCC_COMPILE_ARGS) -o start.o start.S
-
-lab1.o: lab1.S
-	$(CROSS_COMPILE)gcc $(GCC_COMPILE_ARGS) -o lab1.o lab1.S
-
-lab1_v2.bin: lab1_v2.S lab1_v2.ld
-	$(CROSS_COMPILE)gcc $(GCC_COMPILE_ARGS) -o lab1_v2.o lab1_v2.S
-	$(CROSS_COMPILE)gcc lab1_v2.o -mcpu=cortex-m4 -mthumb -Wall \
-		--specs=nosys.specs -nostdlib -lgcc -T./lab1_v2.ld \
-		-o lab1_v2.elf
-	$(CROSS_COMPILE)objcopy -O binary lab1_v2.elf lab1_v2.bin
-
 qemu: build
 	qemu-system-gnuarmeclipse --verbose --verbose --board STM32F4-Discovery \
 		--mcu STM32F407VG -d unimp,guest_errors \

lab1.S

@@ -1,33 +0,0 @@
-.syntax unified
-.cpu cortex-m4
-.thumb
-
-.global lab1_v1
-
-#define A 0xED76
-#define B 0xFA53
-#define C 10
-
-lab1_v1:
-    push.n {r0, r1, r2}
-
-    ldr.n r0, =A
-    ldr.n r1, =B
-
-    and r0, r1
-
-    mov r1, #C
-    mov r2, 1
-
-    _fac:
-    mul r2, r2, r1
-    sub r1, #1
-    cmp.n r1, #1
-    bgt _fac
-
-    add r2, r2, r0, lsr #1
-    mov r11, r2
-
-    pop {r0, r1, r2}
-
-    mov pc, lr

lab1_v2.S

@@ -1,82 +0,0 @@
-.syntax unified
-.cpu cortex-m4
-.thumb
-
-.macro BKPT_WRITE addr_src
-    mov r1, \addr_src
-    mov r0, 0x4
-    bkpt 0xAB
-.endm
-
-#define A 0x0321
-#define B 0x7005
-#define C 0x0050
-
-.section .text
-
-lab1_v2:
-    push.n {lr}
-
-    bl calculate_formula_v2
-    bl int_to_str
-
-    pop.n {pc}
-
-calculate_formula_v2:
-    ldr r0, =A
-    ldr r1, =B
-    ldr r2, =C
-
-    cmp r0, r1
-    bgt gret
-    blt less
-
-    same: @ default
-    add r2, r0, r2, lsr #3
-    add r0, r2, r1
-    b finish
-
-    gret:
-    rsb r0, r0, #192
-    sub r0, r0, r1
-    add r0, r2, r0, lsl #2
-    b finish
-
-    less:
-    orr r1, r1, r2
-    mul r0, r0, r1
-
-    finish:
-    mov r10, r0
-    mov pc, lr
-
-int_to_str:
-    mov r3, sp
-
-    @ write newline + NULL terminator
-    mov r5, #0x000A
-    strh r5, [r3, #-2]!
-
-    @ --- handmade modulo ---
-    mov r4, #10
-
-    iterate:
-    mov  r1, r0       @ save orig to r1
-    udiv r0, r0, r4   @ orig/10 and overwrite old orig value
-    mul  r2, r0, r4   @ orig/10*10, place separately
-    subs r5, r1, r2   @ orig - orig/10*10 => modulo (and update flags)
-
-    beq check_if_pending_digits_exist
-    proceed_with_conversion:
-
-    add r5, #48           @ int -> char (only digits, so it's fine)
-    strb r5, [r3, #-1]!   @ write next char to RAM
-    b iterate
-
-    check_if_pending_digits_exist:
-    cmp r0, #0
-    bne proceed_with_conversion
-
-    BKPT_WRITE r3
-
-    mov pc, lr

lab1_v2.ld

@@ -1,4 +0,0 @@
-MEMORY
-{
-    RAM (rwx) : ORIGIN = 0x20000000, LENGTH = 128K
-}

ldscript.ld

@@ -5,4 +5,3 @@ MEMORY
 }
 
 __stack_start = ORIGIN(RAM) + LENGTH(RAM);
-__ram_start = ORIGIN(RAM);

start.S

@@ -2,98 +2,9 @@
 .cpu cortex-m4
 .thumb
 
-.equ SYSTICK_OFFSET, 0xE000E010
-.equ RCC_OFFSET, 0x40023800
-.equ GPIOD_OFFSET, 0x40020C00
-
-.section .text
-
 vtable:
     .word __stack_start
     .word __hard_reset__+1
-    .align 2
-v2_img_start:
-    .incbin "lab1_v2.bin"
-    .align 2
-v2_img_end: @ ==__hard_reset__
 
 __hard_reset__:
-    bl setup_leds
+    b __hard_reset__
-    bl load_systick_timer
-    bl lab1_v1
-
-    bl bootload_v2
-
-    readloop:
-    ldr.n r0, [r7, #8]
-    wfi
-    b.n readloop
-
-load_systick_timer:
-    @ SysTick_LOAD
-    ldr.n r7, =SYSTICK_OFFSET
-    mov r1, #0x1
-    lsl r1, #20
-    str.n r1, [r7, #4]
-
-    @ SysTick_CTRL
-    mov r1, #0x1
-    str.n r1, [r7]
-
-    mov pc, lr
-
-bootload_v2:
-    push {lr}
-
-    @ bootload to ram
-    ldr.n r0, =v2_img_start
-    ldr.n r1, =v2_img_end
-    ldr.n r3, =__ram_start
-
-    copy_loop:
-    ldr r2, [r0], #4
-    str r2, [r3], #4
-    cmp.n r0, r1
-    bne.n copy_loop
-
-    ldr.n r3, =__ram_start
-    add r3, r3, #1
-
-    push {r3}
-    blx r3
-    pop {r3}
-
-    @ patch A
-    ldr r0, =0x707ff64d @ 0xDF7F
-    str r0, [r3, #0xb]
-
-    push {r3}
-    blx r3
-    pop {r3}
-
-    @ patch A and B
-    ldr r0, =0x000af240 @ 0x000A
-    str r0, [r3, #0xb]
-    ldr r0, =0x010af240 @ 0x000A
-    str r0, [r3, #0xf]
-
-    blx r3
-
-    pop {pc}
-
-setup_leds:
-    @ RCC reset & enable GPIOD
-    ldr r0, =RCC_OFFSET
-    mov r1, #0x8
-    str r1, [r0, #0x30] @ ENABLE
-
-    @ GPIOD config
-    ldr r0, =GPIOD_OFFSET
-
-    ldr r1, =0x55000000
-    str r1, [r0] @ Mode Register
-
-    mov r1, #0xF000
-    str r1, [r0, #0x14] @ Output Data Register
-
-    mov pc, lr