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Difference between revisions of "arm/aarch64"
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== Overview == | == Overview == | ||
The AArch64 execution state was introduced with the {{\\|ARMv8}} ISA for machines executing {{\\|A64}} instructions. A machine in AArch64 can only execute A64 instructions and cannot execute {{\\|A32}} or {{\\|T32}} instructions. However, unlike in {{\\|AArch32}}, in the 64-bit state, instructions can access both the 64-bit and 32-bit registers. | The AArch64 execution state was introduced with the {{\\|ARMv8}} ISA for machines executing {{\\|A64}} instructions. A machine in AArch64 can only execute A64 instructions and cannot execute {{\\|A32}} or {{\\|T32}} instructions. However, unlike in {{\\|AArch32}}, in the 64-bit state, instructions can access both the 64-bit and 32-bit registers. | ||
| + | |||
| + | == Calling convention == | ||
| + | {{see also|calling convention}} | ||
| + | Under AArch64, the first eight registers are used for passing parameters into a subroutine as well as to return a result value set. Generally, X0 through X18 can corrupt while X19-X29 must be preserved. | ||
| + | |||
| + | {| class="wikitable" | ||
| + | |- | ||
| + | ! Register !! Role !! Requirement | ||
| + | |- | ||
| + | | X0 - X7 || Parameter/result registers || rowspan="5" | Can Corrupt | ||
| + | |- | ||
| + | | X8 || Indirect result location register | ||
| + | |- | ||
| + | | X9 - X15 || Temporary registers | ||
| + | |- | ||
| + | | X16 - X17 || Intra-procedure call temporary | ||
| + | |- | ||
| + | | X18 || Platform register, otherwise temporary | ||
| + | |- | ||
| + | | X19 - X29 || Callee-saved register || Must preserve | ||
| + | |- | ||
| + | | X30 || Link Register || Can Corrupt | ||
| + | |} | ||
{{stub}} | {{stub}} | ||
Revision as of 15:48, 20 September 2018
| ARM ISA | |
| General | |
| Variants | |
| Extensions | |
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AArch64 is the 64-bit execution state of the ARMv8 ISA. A machine in this state executes operates on the A64 instruction set. This is in contrast to the AArch32 which describes the classical 32-bit ARM execution state.
Overview
The AArch64 execution state was introduced with the ARMv8 ISA for machines executing A64 instructions. A machine in AArch64 can only execute A64 instructions and cannot execute A32 or T32 instructions. However, unlike in AArch32, in the 64-bit state, instructions can access both the 64-bit and 32-bit registers.
Calling convention
- See also: calling convention
Under AArch64, the first eight registers are used for passing parameters into a subroutine as well as to return a result value set. Generally, X0 through X18 can corrupt while X19-X29 must be preserved.
| Register | Role | Requirement |
|---|---|---|
| X0 - X7 | Parameter/result registers | Can Corrupt |
| X8 | Indirect result location register | |
| X9 - X15 | Temporary registers | |
| X16 - X17 | Intra-procedure call temporary | |
| X18 | Platform register, otherwise temporary | |
| X19 - X29 | Callee-saved register | Must preserve |
| X30 | Link Register | Can Corrupt |
 |
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