Added startup code, updated ldscript.

CMakeLists.txt

@@ -1,16 +1,21 @@
 cmake_minimum_required(VERSION 3.10)
 
+enable_language(ASM)
+
 project(hello)
 
-set(TARGET_SRCS
+set(TARGET_LDSCRIPT "${CMAKE_SOURCE_DIR}/stx7105.ld")
+
+set(TARGET_SOURCES
     "src/main.c"
+    "startup_stx7105.S"
 )
 
 set(TARGET_INCLUDES
     "include"
 )
 
-set(TARGET_FLAGS_HARDWARE "-m4")
+set(TARGET_FLAGS_HARDWARE "-m4-300 -ml")
 
 set(CMAKE_C_FLAGS_DEBUG          "-DDEBUG -g -O0")
 set(CMAKE_CXX_FLAGS_DEBUG        "-DDEBUG -g -O0")
@@ -22,4 +27,13 @@ set(CMAKE_EXE_LINKER_FLAGS_RELEASE "-flto")
 
 set(CMAKE_C_FLAGS          "${TARGET_FLAGS_HARDWARE} -Wall")
 set(CMAKE_CXX_FLAGS        "${TARGET_FLAGS_HARDWARE} -Wall")
-set(CMAKE_EXE_LINKER_FLAGS "${TARGET_FLAGS_HARDWARE} -Wall")
+set(CMAKE_EXE_LINKER_FLAGS "${TARGET_FLAGS_HARDWARE} -Wall -lc -lm -nostartfiles -Wl,--print-memory-usage")
+
+add_compile_definitions(TARGET_DEFS)
+include_directories(TARGET_INCLUDES)
+
+add_executable(${CMAKE_PROJECT_NAME}.elf ${TARGET_SOURCES})
+target_link_options(${CMAKE_PROJECT_NAME}.elf
+    PRIVATE "-T${TARGET_LDSCRIPT}"
+    PRIVATE "-Wl,-Map=${CMAKE_PROJECT_NAME}.map"
+)

startup_stx7105.S

@@ -1,5 +1,67 @@
-.global _start
+    .section .text.init, "ax"
+    .global _start
 
 _start:
     nop
-    nop
+    nop
+    mov.l stack_k, sp /* Setup R15(SP) */
+
+
+copy_data:
+    mov.l sidata_k, r0
+    mov.l sdata_k, r1
+    mov.l edata_k, r2
+
+loop_copy_data:
+    mov.l @r0+, r3 /* Load a word to r3 from [sidata], with post-increment of 4 */
+    mov.l r3, @r1  /* Store the word in r3 to [sdata] */
+    add #4, r1 /* Increment sdata pointer */
+    cmp/ge r1, r2
+    bt loop_copy_data
+
+zero_bss:
+    mov.l edata_k, r0
+    mov.l end_k, r1
+    mov #0, r2
+
+loop_zero_bss:
+    mov.l r2, @r0
+    add #4, r0
+    cmp/ge r0, r1
+    bt loop_zero_bss
+
+setup_fpu:
+    mov.l set_fpscr_k, r1
+    jsr @r1
+    mov #0, r4
+    lds r3, fpscr
+
+
+    mov.l main_k,r0
+    jsr @r0
+    or r0, r0
+
+    mov r0, r4
+    mov.l exit_k, r0
+    jsr @r0
+    or r0, r0
+
+/* It would be more efficient by using indirect addressing instead of 8 instructions... */
+
+    .align 2
+set_fpscr_k:
+    .long ___set_fpscr
+stack_k:
+    .long _stack
+sidata_k:
+    .long _sidata
+sdata_k:
+    .long _sdata
+edata_k:
+    .long _edata
+end_k:
+    .long _end
+main_k:
+    .long _main /* Same address as main */
+exit_k:
+    .long _exit

stx7105.ld

@@ -1,7 +1,56 @@
-MEMORY {
 
+HEAP_SIZE  = 0x10000;
+STACK_SIZE = 0x10000;
+
+ENTRY(_start)
+
+/* For bare-metal applications, we use 29-bit addressing mode. */
+
+MEMORY {
+    EMI  (rx) : ORIGIN = 0x00000000, LENGTH = 0x00100000 /* EMI physical address: 0x0000_0000 */
+    LMI (rwx) : ORIGIN = 0x0C000000, LENGTH = 0x10000000 /* LMI physical address: 0x0C00_0000 */
 }
 
 SECTIONS {
-    
+    .text : {
+        . = ALIGN(4);
+        *(.text.init)
+        *(.text)
+        *(.text*)
+        *(.rodata)
+        *(.rodata*)
+    } >EMI
+
+    .data : {
+        . = ALIGN(4);
+        _sdata = .;
+        *(.data)
+        *(.data*)
+        _edata = .;
+    } >LMI AT >EMI
+
+    _sidata = LOADADDR(.data);
+
+    .bss : {
+        . = ALIGN(4);
+        __bss_start = .;
+        *(.bss)
+        *(.bss*)
+        *(COMMON)
+        _end = ALIGN(8);
+        __end = _end;
+    } >LMI
+
+    .heap : {
+        . = ALIGN(8);
+        . += HEAP_SIZE;
+    }
+
+    .stack : {
+        . = ALIGN(8);
+        . += STACK_SIZE;
+    }
+
+    _stack = ORIGIN(LMI) + LENGTH(LMI);
+    PROVIDE(__stack = _stack);
 }