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Implementation of alloca() standard C routine.
Distributed under the Boost Software License 1.0. (See accompanying file LICENSE)
Walter Bright
void* __alloca(int nbytes);
Allocate data from the caller's stack frame. This is a 'magic' function that needs help from the compiler to work right, do not change its name, do not call it from other compilers.

Input nbytes number of bytes to allocate ECX address of variable with # of bytes in locals This is adjusted upon return to reflect the additional size of the stack frame.

EAX allocated data, null if stack overflows