Commit 5894be94c8
Changed files (1)
doc/langref.html.in
@@ -5393,7 +5393,6 @@ pub fn parseU64(buf: []const u8, radix: u8) !u64 {
// x *= radix
var ov = @mulWithOverflow(x, radix);
if (ov[1] != 0) return error.OverFlow;
-
// x += digit
ov = @addWithOverflow(ov[0], digit);
@@ -6067,7 +6066,7 @@ struct Foo *do_a_thing(void) {
<p>Zig code</p>
{#syntax_block|zig|call_malloc_from_zig.zig#}
// malloc prototype included for reference
-extern fn malloc(size: size_t) ?*u8;
+extern fn malloc(size: usize) ?*u8;
fn doAThing() ?*Foo {
const ptr = malloc(1234) orelse return null;
@@ -7479,64 +7478,66 @@ pub fn syscall3(number: usize, arg1: usize, arg2: usize, arg3: usize) usize {
<p>
Dissecting the syntax:
</p>
- {#syntax_block|zig|Assembly Syntax Explained#}
-// Inline assembly is an expression which returns a value.
-// the `asm` keyword begins the expression.
-_ = asm
-// `volatile` is an optional modifier that tells Zig this
-// inline assembly expression has side-effects. Without
-// `volatile`, Zig is allowed to delete the inline assembly
-// code if the result is unused.
-volatile (
-// Next is a comptime string which is the assembly code.
-// Inside this string one may use `%[ret]`, `%[number]`,
-// or `%[arg1]` where a register is expected, to specify
-// the register that Zig uses for the argument or return value,
-// if the register constraint strings are used. However in
-// the below code, this is not used. A literal `%` can be
-// obtained by escaping it with a double percent: `%%`.
-// Often multiline string syntax comes in handy here.
+ {#code_begin|syntax|Assembly Syntax Explained#}
+pub fn syscall1(number: usize, arg1: usize) usize {
+ // Inline assembly is an expression which returns a value.
+ // the `asm` keyword begins the expression.
+ return asm
+ // `volatile` is an optional modifier that tells Zig this
+ // inline assembly expression has side-effects. Without
+ // `volatile`, Zig is allowed to delete the inline assembly
+ // code if the result is unused.
+ volatile (
+ // Next is a comptime string which is the assembly code.
+ // Inside this string one may use `%[ret]`, `%[number]`,
+ // or `%[arg1]` where a register is expected, to specify
+ // the register that Zig uses for the argument or return value,
+ // if the register constraint strings are used. However in
+ // the below code, this is not used. A literal `%` can be
+ // obtained by escaping it with a double percent: `%%`.
+ // Often multiline string syntax comes in handy here.
\\syscall
-// Next is the output. It is possible in the future Zig will
-// support multiple outputs, depending on how
-// https://github.com/ziglang/zig/issues/215 is resolved.
-// It is allowed for there to be no outputs, in which case
-// this colon would be directly followed by the colon for the inputs.
- :
-// This specifies the name to be used in `%[ret]` syntax in
-// the above assembly string. This example does not use it,
-// but the syntax is mandatory.
- [ret]
-// Next is the output constraint string. This feature is still
-// considered unstable in Zig, and so LLVM/GCC documentation
-// must be used to understand the semantics.
-// http://releases.llvm.org/10.0.0/docs/LangRef.html#inline-asm-constraint-string
-// https://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html
-// In this example, the constraint string means "the result value of
-// this inline assembly instruction is whatever is in $rax".
- "={rax}"
-// Next is either a value binding, or `->` and then a type. The
-// type is the result type of the inline assembly expression.
-// If it is a value binding, then `%[ret]` syntax would be used
-// to refer to the register bound to the value.
- (-> usize)
-// Next is the list of inputs.
-// The constraint for these inputs means, "when the assembly code is
-// executed, $rax shall have the value of `number` and $rdi shall have
-// the value of `arg1`". Any number of input parameters is allowed,
-// including none.
- : [number] "{rax}" (number),
- [arg1] "{rdi}" (arg1)
-// Next is the list of clobbers. These declare a set of registers whose
-// values will not be preserved by the execution of this assembly code.
-// These do not include output or input registers. The special clobber
-// value of "memory" means that the assembly writes to arbitrary undeclared
-// memory locations - not only the memory pointed to by a declared indirect
-// output. In this example we list $rcx and $r11 because it is known the
-// kernel syscall does not preserve these registers.
- : "rcx", "r11"
-);
- {#end_syntax_block#}
+ // Next is the output. It is possible in the future Zig will
+ // support multiple outputs, depending on how
+ // https://github.com/ziglang/zig/issues/215 is resolved.
+ // It is allowed for there to be no outputs, in which case
+ // this colon would be directly followed by the colon for the inputs.
+ :
+ // This specifies the name to be used in `%[ret]` syntax in
+ // the above assembly string. This example does not use it,
+ // but the syntax is mandatory.
+ [ret]
+ // Next is the output constraint string. This feature is still
+ // considered unstable in Zig, and so LLVM/GCC documentation
+ // must be used to understand the semantics.
+ // http://releases.llvm.org/10.0.0/docs/LangRef.html#inline-asm-constraint-string
+ // https://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html
+ // In this example, the constraint string means "the result value of
+ // this inline assembly instruction is whatever is in $rax".
+ "={rax}"
+ // Next is either a value binding, or `->` and then a type. The
+ // type is the result type of the inline assembly expression.
+ // If it is a value binding, then `%[ret]` syntax would be used
+ // to refer to the register bound to the value.
+ (-> usize)
+ // Next is the list of inputs.
+ // The constraint for these inputs means, "when the assembly code is
+ // executed, $rax shall have the value of `number` and $rdi shall have
+ // the value of `arg1`". Any number of input parameters is allowed,
+ // including none.
+ : [number] "{rax}" (number),
+ [arg1] "{rdi}" (arg1)
+ // Next is the list of clobbers. These declare a set of registers whose
+ // values will not be preserved by the execution of this assembly code.
+ // These do not include output or input registers. The special clobber
+ // value of "memory" means that the assembly writes to arbitrary undeclared
+ // memory locations - not only the memory pointed to by a declared indirect
+ // output. In this example we list $rcx and $r11 because it is known the
+ // kernel syscall does not preserve these registers.
+ : "rcx", "r11"
+ );
+}
+ {#code_end#}
<p>
For x86 and x86_64 targets, the syntax is AT&T syntax, rather than the more
popular Intel syntax. This is due to technical constraints; assembly parsing is
@@ -7892,7 +7893,7 @@ fn add(a: i32, b: i32) i32 {
{#syntax#}@call{#endsyntax#} allows more flexibility than normal function call syntax does. The
{#syntax#}CallModifier{#endsyntax#} enum is reproduced here:
</p>
- {#syntax_block|zig|builtin.CallModifier struct#}
+ {#code_begin|syntax|builtin.CallModifier struct#}
pub const CallModifier = enum {
/// Equivalent to function call syntax.
auto,
@@ -7926,7 +7927,7 @@ pub const CallModifier = enum {
/// compile-time, a compile error is emitted instead.
compile_time,
};
- {#end_syntax_block#}
+ {#code_end#}
{#header_close#}
{#header_open|@cDefine#}