diff options
Diffstat (limited to 'libgloss/mn10300/crt0_redboot.S')
| -rw-r--r-- | libgloss/mn10300/crt0_redboot.S | 97 |
1 files changed, 97 insertions, 0 deletions
diff --git a/libgloss/mn10300/crt0_redboot.S b/libgloss/mn10300/crt0_redboot.S new file mode 100644 index 000000000..c3667c542 --- /dev/null +++ b/libgloss/mn10300/crt0_redboot.S @@ -0,0 +1,97 @@ +/* + * crt0_redboot.S -- Minimal startup file for MN10300 targets running Redboot. + * + * Copyright (c) 2001 Red Hat, Inc. + * Derived from crt0_cygmon.S - Copyright (c) 1995, 1996, 1997, 2000 Red Hat, Inc. + * + * The authors hereby grant permission to use, copy, modify, distribute, + * and license this software and its documentation for any purpose, provided + * that existing copyright notices are retained in all copies and that this + * notice is included verbatim in any distributions. No written agreement, + * license, or royalty fee is required for any of the authorized uses. + * Modifications to this software may be copyrighted by their authors + * and need not follow the licensing terms described here, provided that + * the new terms are clearly indicated on the first page of each file where + * they apply. + */ + +/* + * This file contains the minimal startup code necessary. + * This will not do any hardware initialization. It is assumed that we are talking to Redboot + * and therefore the hardware will be initialized properly. + */ + +/* + * Set up some room for a stack. We just grab a chunk of memory. + */ +#define STACK_SIZE 0x4000 +#define GLOBAL_SIZE 0x2000 + +#define STARTUP_STACK_SIZE 0x0100 + + .comm __memsize, 12 + .comm __lstack, STARTUP_STACK_SIZE + .comm __stackbase,4 + + .section .text + .global _start +_start: + /* + * Setup a small stack so we can run some C code, + * and get the usable memory size. + */ + mov __lstack,a0 + add STARTUP_STACK_SIZE-4,a0 + mov a0,sp + + /* + * zero out the bss section. + */ + .global __memsize + .global _get_mem_info +zerobss: + mov __bss_start, a0 # These variables are defined in the linker script + mov _end, a1 + + cmp a0, a1 # If no bss, then do nothing + beq 7f + + clr d0 +3: + movbu d0,(a0) # Clear a byte and bump pointer + inc a0 + cmp a0, a1 + bne 3b + +7: + /* + * Setup the stack pointer -- + * get_mem_info returns the top of memory, so just use that In + * addition, we must subtract 24 bytes for the 3 8 byte + * arguments to main, in case main wants to write them back to + * the stack. The caller is supposed to allocate stack space + * for parameters in registers in the old MIPS ABIs. We must + * do this even though we aren't passing arguments, because + * main might be declared to have them. + * Some ports need a larger alignment for the stack, so we + * subtract 32, which satisifes the stack for the arguments and + * keeps the stack pointer better aligned. + */ + mov __memsize, d0 + call _get_mem_info,[],0 + + sub 32, a0 + mov a0, sp + + mov __stackbase, a1 + mov a0, (a1) # keep this for future ref + + call ___main,[],0 # Call __main to run ctors/dtors + clr d0 + clr d1 + mov d0, (4,sp) + or 0x0800,psw # Enable interrupts + call _main,[],0 # Call main program + call _exit,[],0 + +/* EOF crt0_redboot.S */ |