targets: move target-specific files to this directory

targets/arduino.json

@@ -2,5 +2,5 @@
 	"llvm-target": "avr-atmel-none",
 	"build-tags": ["avr", "avr8", "atmega", "atmega328p", "js", "wasm"],
 	"linker": "avr-gcc",
-	"pre-link-args": ["-nostdlib", "-T", "avr.ld", "-Wl,--gc-sections", "avr.S"]
+	"pre-link-args": ["-nostdlib", "-T", "targets/avr.ld", "-Wl,--gc-sections", "targets/avr.S"]
 }

targets/arm.ld

@@ -0,0 +1,82 @@
+
+MEMORY
+{
+    FLASH_TEXT (rw) : ORIGIN = 0x00000000, LENGTH = 256K /* .text */
+    RAM (xrw)       : ORIGIN = 0x20000000, LENGTH = 64K
+}
+
+_stack_size = 2K;
+
+/* define output sections */
+SECTIONS
+{
+    /* The program code and other data goes into FLASH */
+    .text :
+    {
+        _stext = .;
+        . = ALIGN(4);
+        KEEP(*(.isr_vector))
+        *(.text)           /* .text sections (code) */
+        *(.text*)          /* .text* sections (code) */
+        *(.rodata)         /* .rodata sections (constants, strings, etc.) */
+        *(.rodata*)        /* .rodata* sections (constants, strings, etc.) */
+        . = ALIGN(4);
+        _etext = .;        /* define a global symbol at end of code */
+    } >FLASH_TEXT
+
+    /* Put the stack at the bottom of RAM, so that the application will
+     * crash on stack overflow instead of silently corrupting memory.
+     * See: http://blog.japaric.io/stack-overflow-protection/ */
+    .stack :
+    {
+        . = ALIGN(4);
+        . += _stack_size;
+        __StackTop = .;
+    } >RAM
+
+    /* This is the initialized data section
+    The program executes knowing that the data is in the RAM
+    but the loader puts the initial values in the FLASH (inidata).
+    It is one task of the startup to copy the initial values from FLASH to RAM. */
+    .data :
+    {
+        . = ALIGN(4);
+        _sdata = .;        /* create a global symbol at data start; used by startup code in order to initialise the .data section in RAM */
+        *(.data)           /* .data sections */
+        *(.data*)          /* .data* sections */
+
+        . = ALIGN(4);
+        _edata = .;        /* define a global symbol at data end; used by startup code in order to initialise the .data section in RAM */
+    } >RAM AT>FLASH_TEXT
+
+    /* Uninitialized data section */
+    .bss :
+    {
+        . = ALIGN(4);
+        _sbss = .;         /* define a global symbol at bss start; used by startup code */
+        *(.bss)
+        *(.bss*)
+        *(COMMON)
+
+        . = ALIGN(4);
+        _ebss = .;         /* define a global symbol at bss end; used by startup code and GC */
+    } >RAM
+
+    /DISCARD/ :
+    {
+        *(.ARM.exidx.*)
+        *(.ARM.attributes)
+        *(.stack) /* from nrfx */
+        *(.heap)  /* from nrfx */
+    }
+}
+
+/* For the nrfx startup file. */
+__etext = _etext;
+__data_start__ = _sdata;
+__bss_start__ = _sbss;
+__bss_end__ = _ebss;
+
+/* For the memory allocator. */
+_heap_start = _ebss;
+_heap_end = ORIGIN(RAM) + LENGTH(RAM);

targets/avr.S

@@ -0,0 +1,62 @@
+.section .isr
+isr:
+    rjmp reset
+
+.org 0x18 ; WDT
+    rjmp wdt
+
+; Startup code
+.section .reset
+.org 26
+reset:
+    clr  r1          ; r1 is expected to be 0 by the C calling convention
+
+    ; Zero .bss
+clear_bss:
+    ldi  xl, lo8(_sbss)
+    ldi  xh, hi8(_sbss)
+clear_bss_loop:
+    ldi  yl, lo8(_ebss)
+    ldi  yh, hi8(_ebss)
+    cp   xl, yl         ; if x == y
+    cpc  xh, yh
+    breq clear_bss_end
+    st   x+, r1         ; zero byte in *x
+    rjmp clear_bss_loop
+clear_bss_end:
+
+    ; Set up the stack pointer.
+    ldi  xl, lo8(_stack_top)
+    ldi  xh, hi8(_stack_top)
+    out  0x3d, xl; SPL
+    out  0x3e, xh; SPH
+
+    ; Enable interrupts.
+    ; TODO: make sure interrupts are started after all initializers have run.
+    sei
+
+    ; main will be placed right after here by the linker script so there's no
+    ; need to jump.
+
+
+; The only thing this WDT handler really does is disable itself, to get out of
+; sleep mode.
+.section .text.wdt
+wdt:
+    push r16
+
+    clr  r16
+    wdr            ; Reset watchdog
+    out  0x34, r16 ; Clear reset reason (MCUSR)
+
+    ; part 1: set WDCE and WDE to enable editing WDTCSR
+    lds  r16, 0x60 ; r16 = WDTCSR
+    ori  r16, 0x18 ; r16 |= WDCE | WDE
+    sts  0x60, r16 ; WDTCSR = r16
+
+    ; part 2: within 4 clock cycles, set the new value for WDTCSR
+    clr  r16
+    sts  0x60, r16 ; WDTCSR = 0
+
+    pop  r16
+    reti

targets/avr.ld

@@ -0,0 +1,43 @@
+
+MEMORY
+{
+    FLASH_TEXT (rw) : ORIGIN = 0, LENGTH = 32256
+    RAM (xrw)       : ORIGIN = 0, LENGTH = 2K
+}
+
+_stack_size = 512;
+
+SECTIONS
+{
+    .text :
+    {
+        KEEP(*(.isr))
+        KEEP(*(.reset))
+        KEEP(*(.text.main)) /* main must follow the reset handler */
+        *(.text.*)
+        *(.rodata)
+        *(.rodata.*)
+    }
+
+    .stack :
+    {
+        . += _stack_size;
+        _stack_top = .;
+    } >RAM
+
+    .data :
+    {
+        *(.data)
+        *(.data*)
+    } >RAM AT>FLASH_TEXT
+
+    .bss :
+    {
+        _sbss = .;
+        *(.bss)
+        *(.bss*)
+        *(COMMON)
+        _ebss = .;
+        _heap_start = .;
+    } >RAM
+}

targets/pca10040.json

@@ -2,5 +2,5 @@
 	"llvm-target": "armv7m-none-eabi",
 	"build-tags": ["nrf", "nrf52", "nrf52832", "js", "wasm"],
 	"linker": "arm-none-eabi-gcc",
-	"pre-link-args": ["-nostdlib", "-nostartfiles", "-mcpu=cortex-m4", "-mthumb", "-T", "arm.ld", "-Wl,--gc-sections", "-fno-exceptions", "-fno-unwind-tables", "-ffunction-sections", "-fdata-sections", "-Os", "-DNRF52832_XXAA", "-D__STARTUP_CLEAR_BSS", "-Ilib/CMSIS/CMSIS/Include", "lib/nrfx/mdk/gcc_startup_nrf51.S", "lib/nrfx/mdk/system_nrf52.c"]
+	"pre-link-args": ["-nostdlib", "-nostartfiles", "-mcpu=cortex-m4", "-mthumb", "-T", "targets/arm.ld", "-Wl,--gc-sections", "-fno-exceptions", "-fno-unwind-tables", "-ffunction-sections", "-fdata-sections", "-Os", "-DNRF52832_XXAA", "-D__STARTUP_CLEAR_BSS", "-Ilib/CMSIS/CMSIS/Include", "lib/nrfx/mdk/gcc_startup_nrf51.S", "lib/nrfx/mdk/system_nrf52.c"]
 }