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I have some given code that uses variable length arrays on the stack in C. I cannot easily change that code to use malloc ed buffers on the heap, since I am working on some stuff where I have no operating system support for dynamic memory. However when I test my method the stack actually get's smashed instead (i.e. the SP get's set to a completely bogus address). To figure out what is going on I had a look at the assembly and I was completely confused by the compiler output. I am running the code on a pandaboard ES (OMAP4460 ARM processor). In order to test how variable size arrays on the stack are actually compiled, I produced a simple working test program. However again the code was much too confusing for me to understand. Here is what I do not understand: When I compile a simple function: int test_method(size_t i) { unsigned char buffer[10]; return -1; } I get some very simple assembler code: 80003a68 <test_method>: 80003a68: b480 push {r7} ; store frame pointer 80003a6a: b087 sub sp, #28 ; make stack frame (size 28) 80003a6c: af00 add r7, sp, #0 ; set frame pointer 80003a6e: 6078 str r0, [r7, #4]; store parameter on stack 80003a70: f04f 0300 mov.w r3, #0 ; load return value 80003a74: 4618 mov r0, r3 ; put return value in return register 80003a76: f107 071c add.w r7, r7, #28 ; destroy stack frame 80003a7a: 46bd mov sp, r7 ; ... 80003a7c: bc80 pop {r7} ; pop stored frame pointer 80003a7e: 4770 bx lr ; return But when I try this with a variable size array using the following code: int test_method(size_t i) { unsigned char buffer[i]; return 0; } I get t

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