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emscripten-core
GitHub Repository: emscripten-core/emscripten
 Path: blob/main/system/lib/compiler-rt/stack_limits.S
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.globl emscripten_stack_init

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.globl emscripten_stack_set_limits

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.globl emscripten_stack_get_free

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.globl emscripten_stack_get_base

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.globl emscripten_stack_get_end

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#ifdef __wasm64__

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#define PTR i64

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#define ALIGN 3

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#define PTRSTORE .int64

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#else

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#define PTR i32

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#define ALIGN 2

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#define PTRSTORE .int32

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#endif

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.globaltype __stack_pointer, PTR

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.section .globals,"",@

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# TODO(sbc): It would be nice if these were initialized directly

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# using PTR.const rather than using the `emscripten_stack_init`

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.globaltype __stack_end, PTR

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__stack_end:

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.globaltype __stack_base, PTR

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__stack_base:

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.section .text,"",@

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emscripten_stack_get_base:

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  .functype emscripten_stack_get_base () -> (PTR)

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  global.get __stack_base

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  end_function

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emscripten_stack_get_end:

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  .functype emscripten_stack_get_end () -> (PTR)

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  global.get __stack_end

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  end_function

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emscripten_stack_init:

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  # Initialize __stack_end and __stack_base.

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  # This must be called before emscripten_stack_get_end,

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  # emscripten_stack_get_base, or emscripten_stack_get_free are called

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  .functype emscripten_stack_init () -> ()

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  # What llvm calls __stack_high is the high address from where it grows

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  # downwards.  We call this the stack base here in emscripten.

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#ifdef __PIC__

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  global.get __stack_high@GOT

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#else

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  PTR.const __stack_high

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#endif

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  global.set __stack_base

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  # What llvm calls __stack_low is that end of the stack

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#ifdef __PIC__

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  global.get __stack_low@GOT

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#else

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  PTR.const __stack_low

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#endif

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  # Align up to 16 bytes

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  PTR.const 0xf

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  PTR.add

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  PTR.const -0x10

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  PTR.and

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  global.set __stack_end

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  end_function

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emscripten_stack_set_limits:

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  .functype emscripten_stack_set_limits (PTR, PTR) -> ()

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  local.get 0

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  global.set __stack_base

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  local.get 1

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  global.set __stack_end

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  end_function

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emscripten_stack_get_free:

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  .functype emscripten_stack_get_free () -> (PTR)

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  global.get __stack_pointer

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  global.get __stack_end

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  PTR.sub

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  end_function

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# Add emscripten_stack_init to static ctors

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.section .init_array.1,"",@

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.p2align ALIGN

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PTRSTORE emscripten_stack_init

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