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Updated syntax.md to remove references to % numerical ids.

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Andrew Woloszyn 2015-09-28 11:09:23 -04:00 committed by David Neto
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syntax.md
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@ -43,6 +43,7 @@ otherwise generate an error.
(This is supported by the assembler but not yet by the disassembler.
TODO(dneto): Add disassembler support for emitting mask expressions.)
* an injected immediate integer: `!<integer>`. See [below](#immediate).
* an ID, e.g. `%foo`. See [below](#id).
## Assignment-oriented Assembly Form
<a name="assignment-form"></a>
@ -70,18 +71,21 @@ can also be written as:
```
## ID Definitions & Usage
<a name="id"></a>
An ID definition pertains to the `<result-id>` of an OpCode, and ID usage is any
input to an OpCode. All IDs are prefixed with `%`. To differentiate between
defs and uses, we suggest using the second format shown in the above example.
An ID definition pertains to the `<result-id>` of an OpCode, and ID usage is a
use of an ID as an input to an OpCode.
The ID names do not necessarily have to be numerical. Furthermore to avoid
aliasing names, if a name is numerical, it will not necessarily map to the
corresponding numerical id in the generated spirv. The same ID definition and
usage prefixes apply. Names may contain any character in
['0-9|a-z|A-Z|\_'] The following example will result in identical SPIR-V binary
as the example above.
An ID in the assembly language begins with `%` and must be followed by a name
consisting of one or more letters, numbers or underscore characters.
For every ID in the assembly program, the assembler generates a unique number
called the ID's internal number. Then each ID reference translates into its
internal number in the SPIR-V output. Internal numbers are unique within the
compilation unit: no two IDs in the same unit will share internal numbers.
The disassembler generates IDs where the name is always a decimal number
greater than 0.
```
OpCapability Shader
OpMemoryModel Logical Simple
@ -95,8 +99,6 @@ as the example above.
OpFunctionEnd
```
## Arbitrary Integers
<a name="immediate"></a>
@ -155,10 +157,7 @@ follows:
as defined in the SPIR-V specification for Literal Number.
* If the word is a string literal, it outputs a sequence of words representing
the string as defined in the SPIR-V specification for Literal String.
* If the word is an ID, it outputs the ID's internal number. If no such number
exists yet, a unique new one will be generated. (Uniqueness is at the
translation-unit level: no other ID in the same translation unit will have the
same number.)
* If the word is an ID, it outputs the ID's internal number.
* If the word is another `!<integer>`, it outputs that integer.
* Any other word causes the assembler to quit with an error.
@ -178,8 +177,9 @@ Note that this has some interesting consequences, including:
successful assembly.
* The `<result-id>` on the left-hand side of an assignment cannot be
a`!<integer>`. But it can be a number prefixed by `%`, which still gives the
user control over its value.
a `!<integer>`. The `<result-id>` can be still be manually
controlled if desired by using the
[Canonical Assembly Form](#assignment-form).
* The `=` sign cannot be processed by the alternate parsing mode if the OpCode
following it is a `!<integer>`.