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#pragma once
#include "Code/Params.h"
namespace code {
namespace arm64 {
STORM_PKG(core.asm.arm64);
/**
* Implements the logic for laying out parameters on the stack and into registers.
*
* On ARM64 parameters are passed according to the following rules:
* - The first eight integer or pointer parameters are passed in registers x0..x7
* - The first eight floating-point arguments are passed in registers d0..d7
* - Any parameters that do not fit in registers are passed on the stack.
* - Composite types that are not "trivial" are passed in memory (replaced by a pointer in the parameter list).
* - Composite types are passed on the stack if they are larger than 16 bytes.
* - Composite types of size up to 16 bytes might be split into two registers.
* - Note: Arguments copied to the stack will have to be aligned to 8 bytes, even
* if their natural alignment is smaller.
* - If a structure contains at most four elements of a single fp-type, it is passed
* as separate values in the fp registers (called a HFA in the ABI).
*
* In summary, some important differences from the X86-64 calling convention are:
* - Each parameter gets allocated to *one* set of registers. It is never split between
* integer registers and fp registers.
* - Return values are handled as "regular" parameters.
* - No special cases with regards to the "this" parameter.
* - Register numbers are "aligned" when large structs are passed.
* - FP registers are *only* used for uniform float parameters. I.e., not if a struct
* contains e.g. 2 floats and 1 double.
*/
class Params : public code::Params {
STORM_CLASS;
public:
// Create an empty parameter layout.
STORM_CTOR Params();
// Get the register containing the parameter.
Reg STORM_FN registerSrc(Nat n) const;
protected:
void STORM_FN resultPrimitive(Primitive p);
void STORM_FN resultComplex(ComplexDesc *desc);
void STORM_FN resultSimple(SimpleDesc *desc);
void STORM_FN addPrimitive(Nat id, Primitive p);
void STORM_FN addComplex(Nat id, ComplexDesc *desc);
void STORM_FN addSimple(Nat id, SimpleDesc *desc);
};
// Create a 'params' object from a list of TypeDesc objects. Note: The result never affects
// the parameter layout on Arm64, so no parameter with the result id will ever appear in the
// returned object.
Params *STORM_FN layoutParams(TypeDesc *result, Array<TypeDesc *> *types);
}
}
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