diff options
| -rw-r--r-- | system-clock/linker/linker_script.ld | 18 | ||||
| -rw-r--r-- | system-clock/src/isr_vector.c | 39 |
2 files changed, 56 insertions, 1 deletions
diff --git a/system-clock/linker/linker_script.ld b/system-clock/linker/linker_script.ld index fe0c14b..b9a8d4b 100644 --- a/system-clock/linker/linker_script.ld +++ b/system-clock/linker/linker_script.ld @@ -1,6 +1,8 @@ MEMORY { flash : org = 0x08000000, len = 256k + sram1 : org = 0x20000000, len = 48k + sram2 : org = 0x10000000, len = 16k } SECTIONS @@ -11,4 +13,20 @@ SECTIONS *(.vectors); /* All .vector sections go here. */ *(.text); /* All .text sections go here. */ } >flash + + .data : { + /* Data segment as defined in the flash. */ + INIT_DATA_VALUES = LOADADDR(.data); + + /* Data segment where it will be in memory. */ + DATA_SEGMENT_START = .; + *(.data); + DATA_SEGMENT_STOP = .; + } >sram1 AT>flash + + BSS_START = .; + .bss : { + *(.bss); + } > sram1 + BSS_END = .; } diff --git a/system-clock/src/isr_vector.c b/system-clock/src/isr_vector.c index a56a8dc..b432732 100644 --- a/system-clock/src/isr_vector.c +++ b/system-clock/src/isr_vector.c @@ -5,9 +5,46 @@ /* Forward-declare the main function. This is implemented in main.c. */ void main(); + +/* These are defined in the linker script. */ +extern uint8_t INIT_DATA_VALUES; +extern uint8_t DATA_SEGMENT_START; +extern uint8_t DATA_SEGMENT_STOP; +extern uint8_t BSS_START; +extern uint8_t BSS_END; + + +/* + * Runs before main. Initializes the data and bss segments by loading them + * into memory. + */ +void init() +{ + uint8_t* src; + uint8_t* dest; + + src = &INIT_DATA_VALUES; + dest = &DATA_SEGMENT_START; + + /* Copy the values from flash into the data segment. */ + while (dest != &DATA_SEGMENT_STOP) { + *(dest ++) = *(src ++); + } + + /* Everything in the BSS segment is set to zero. */ + dest = &BSS_START; + while (dest != &BSS_END) { + *(dest ++) = 0; + } + + + /* Jump to main. */ + main(); +} + const void* vectors[] __attribute__((section(".vectors"))) = { (void *) 0x2000c000, /* Top of stack at top of sram1. 48k */ - main, /* Reset handler */ + init, /* Reset handler */ unhandled_isr, /* NMI */ unhandled_isr, /* Hard Fault */ unhandled_isr, /* MemManage */ |