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Diffstat (limited to 'libgloss/aarch64/crt0.S')
| -rw-r--r-- | libgloss/aarch64/crt0.S | 203 |
1 files changed, 203 insertions, 0 deletions
diff --git a/libgloss/aarch64/crt0.S b/libgloss/aarch64/crt0.S new file mode 100644 index 000000000..601bb2bb1 --- /dev/null +++ b/libgloss/aarch64/crt0.S @@ -0,0 +1,203 @@ +/* Copyright (c) 2009, 2010, 2011, 2012 ARM Ltd. All rights reserved. + + Redistribution and use in source and binary forms, with or without + modification, are permitted provided that the following conditions + are met: + 1. Redistributions of source code must retain the above copyright + notice, this list of conditions and the following disclaimer. + 2. Redistributions in binary form must reproduce the above copyright + notice, this list of conditions and the following disclaimer in the + documentation and/or other materials provided with the distribution. + 3. The name of the company may not be used to endorse or promote + products derived from this software without specific prior written + permission. + + THIS SOFTWARE IS PROVIDED BY ARM LTD ``AS IS'' AND ANY EXPRESS OR IMPLIED + WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF + MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + IN NO EVENT SHALL ARM LTD BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED + TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR + PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF + LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING + NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS + SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ + +#include "newlib.h" +#include "svc.h" + +/* ANSI concatenation macros. */ +#define CONCAT(a, b) CONCAT2(a, b) +#define CONCAT2(a, b) a ## b + +#ifdef __USER_LABEL_PREFIX__ +#define FUNCTION( name ) CONCAT (__USER_LABEL_PREFIX__, name) +#else +#error __USER_LABEL_PREFIX is not defined +#endif + +#ifdef HAVE_INITFINI_ARRAY +#define _init __libc_init_array +#define _fini __libc_fini_array +#endif + + .text +.macro FUNC_START name + .global \name +\name: +.endm + + .align 2 + + FUNC_START _mainCRTStartup + FUNC_START _start + FUNC_START start + +/* Start by setting up a stack */ + + /* Issue Angel SVC to read memory info. + + ptr to ptr to 4 words to receive data. */ + adr x1, .LC0 + mov w0, #AngelSVC_Reason_HeapInfo + AngelSVCAsm AngelSVC + + /* Initialise the stack pointer */ + + /* We currently choose to use the heap_limit field rather than + stack_base because the AEM validation model + returns sane values in the heap fields, but 0 in the stack + fields. Note on the VE AEM model it is necessary to pass + command line options to the AEM in order to define the values + exposed here in the HeapInfo Angel call. */ + ldr x0, .LC0 /* point at returned values */ + ldr x0, [x0, #8] /* get heap_limit */ + + /* Ensure quad-word stack alignment. */ + and x0, x0, #~15 + mov sp, x0 + + /* Setup an initial dummy frame with saved fp=0 and saved lr=0 */ + mov x29, 0 + stp x29, x29, [sp, #-16]! + mov x29, sp + + /* Initialize exception vector table, flatmap, etc. */ + bl FUNCTION (_cpu_init_hook) + + /* Zero the memory in the .bss section. */ + ldr x0, .LC1 /* First arg: start of memory block */ + mov w1, #0 /* Second arg: fill value */ + ldr x2, .LC2 + sub x2, x2, x0 /* Third arg: length of block */ + bl FUNCTION (memset) + + /* Need to set up standard file handles */ + bl FUNCTION (initialise_monitor_handles) + + /* .init and .fini sections are used to create constructors + and destructors. Here we call the _init function and arrange + for _fini to be called at program exit. */ + ldr x0, .Lfini + bl FUNCTION (atexit) + + bl FUNCTION (_init) + + /* Fetch and parse the command line. */ + adr x1, .Lcmdline /* Command line descriptor. */ + mov w0, #AngelSVC_Reason_GetCmdLine + AngelSVCAsm AngelSVC + ldr x8, .Lcmdline + + mov x0, #0 /* argc */ + mov x1, sp /* argv */ + ldr x2, .Lenvp /* envp */ + + /* Put NULL at end of argv array. */ + str x0, [x1, #-8]! + + /* Skip leading blanks. */ +.Lnext: ldrb w3, [x8], #1 + cbz w3, .Lendstr + cmp w3, #' ' + b.eq .Lnext + + mov w4, #' ' /* Terminator is space. */ + + /* See whether we are scanning a quoted string by checking for + opening quote (" or '). */ + subs w9, w3, #'\"' + sub x8, x8, #1 /* Backup if no match. */ + ccmp w9, #('\'' - '\"'), 0x4 /* FLG_Z */, ne + csel w4, w3, w4, eq /* Terminator = quote if match. */ + cinc x8, x8, eq + + /* Push arg pointer to argv, and bump argc. */ + str x8, [x1, #-8]! + add x0, x0, #1 + + /* Find end of arg string. */ +1: ldrb w3, [x8], #1 + cbz w3, .Lendstr + cmp w4, w3 /* Reached terminator? */ + b.ne 1b + + /* Terminate the arg string with NUL char. */ + mov w4, #0 + strb w4, [x8, #-1] + b .Lnext + + /* Reverse argv array. */ +.Lendstr: + add x3, x1, #0 /* sp = &argv[0] */ + add x4, x1, w0, uxtw #3 /* ep = &argv[argc] */ + cmp x4, x3 + b.lo 2f +1: ldr x5, [x4, #-8] /* x5 = ep[-1] */ + ldr x6, [x3] /* x6 = *sp */ + str x6, [x4, #-8]! /* *--ep = x6 */ + str x5, [x3], #8 /* *sp++ = x5 */ + cmp x4, x3 + b.hi 1b +2: + /* Move sp to the 16B boundary below argv. */ + and x4, x1, ~15 + mov sp, x4 + + bl FUNCTION (main) + + b FUNCTION (exit) /* Cannot return. */ + +/* Function initializing exception vector table, flatmap, etc. + Declared as weak symbol so that user can override this definition + by linking in their own version of the function. */ + .weak FUNCTION (_cpu_init_hook) +FUNCTION (_cpu_init_hook): + ret + + .align 3 +.LC0: + .dword HeapBase +.LC1: + .dword __bss_start__ +.LC2: + .dword __bss_end__ +.Lfini: + .dword FUNCTION(_fini) +.Lenvp: + .dword env +.Lcmdline: + .dword CommandLine + .dword 255 + +/* Workspace for Angel calls. */ + .data + .align 3 +/* Data returned by monitor SVC. */ + .global __stack_base__ +HeapBase: .dword 0 +HeapLimit: .dword 0 +__stack_base__: .dword 0 +StackLimit: .dword 0 +env: .dword 0 /* Dummy environment array */ +CommandLine: .space 256,0 /* Maximum length of 255 chars handled. */ |