| ... | @@ -8674,6 +8674,50 @@ test "@wasmMemoryGrow" { | ... | @@ -8674,6 +8674,50 @@ test "@wasmMemoryGrow" { |
| 8674 | {#see_also|@ctz|@clz#} | 8674 | {#see_also|@ctz|@clz#} |
| 8675 | {#header_close#} | 8675 | {#header_close#} |
| 8676 | | 8676 | |
| | 8677 | {#header_open|@prefetch#} |
| | 8678 | <pre>{#syntax#}@prefetch(ptr: anytype, comptime options: std.builtin.PrefetchOptions){#endsyntax#}</pre> |
| | 8679 | <p> |
| | 8680 | This builtin tells the compiler to emit a prefetch instruction if supported by the |
| | 8681 | target CPU. If the target CPU does not support the requested prefetch instruction, |
| | 8682 | this builtin is a noop. This function has no effect on the behavior of the program, |
| | 8683 | only on the performance characteristics. |
| | 8684 | </p> |
| | 8685 | <p> |
| | 8686 | The {#syntax#}ptr{#endsyntax#} argument may be any pointer type and determines the memory |
| | 8687 | address to prefetch. This function does not dereference the pointer, it is perfectly legal |
| | 8688 | to pass a pointer to invalid memory to this function and no illegal behavior will result. |
| | 8689 | </p> |
| | 8690 | <p> |
| | 8691 | The {#syntax#}options{#endsyntax#} argument is the following struct: |
| | 8692 | </p> |
| | 8693 | {#code_begin|syntax|builtin#} |
| | 8694 | /// This data structure is used by the Zig language code generation and |
| | 8695 | /// therefore must be kept in sync with the compiler implementation. |
| | 8696 | pub const PrefetchOptions = struct { |
| | 8697 | /// Whether the prefetch should prepare for a read or a write. |
| | 8698 | rw: Rw = .read, |
| | 8699 | /// 0 means no temporal locality. That is, the data can be immediately |
| | 8700 | /// dropped from the cache after it is accessed. |
| | 8701 | /// |
| | 8702 | /// 3 means high temporal locality. That is, the data should be kept in |
| | 8703 | /// the cache as it is likely to be accessed again soon. |
| | 8704 | locality: u2 = 3, |
| | 8705 | /// The cache that the prefetch should be preformed on. |
| | 8706 | cache: Cache = .data, |
| | 8707 | |
| | 8708 | pub const Rw = enum { |
| | 8709 | read, |
| | 8710 | write, |
| | 8711 | }; |
| | 8712 | |
| | 8713 | pub const Cache = enum { |
| | 8714 | instruction, |
| | 8715 | data, |
| | 8716 | }; |
| | 8717 | }; |
| | 8718 | {#code_end#} |
| | 8719 | {#header_close#} |
| | 8720 | |
| 8677 | {#header_open|@ptrCast#} | 8721 | {#header_open|@ptrCast#} |
| 8678 | <pre>{#syntax#}@ptrCast(comptime DestType: type, value: anytype) DestType{#endsyntax#}</pre> | 8722 | <pre>{#syntax#}@ptrCast(comptime DestType: type, value: anytype) DestType{#endsyntax#}</pre> |
| 8679 | <p> | 8723 | <p> |
Isaac Freund <mail@isaacfreund.com> 2021-12-10 23:06:08+01:00
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