diff options
| -rw-r--r-- | doc/il.txt | 32 |
1 files changed, 29 insertions, 3 deletions
diff --git a/doc/il.txt b/doc/il.txt index cc3e021..2e57290 100644 --- a/doc/il.txt +++ b/doc/il.txt @@ -15,7 +15,7 @@ 2. <@ Types > * <@ Simple Types > * <@ Subtyping > - 3. <@ Constants > + 3. <@ Constants and Vals > 4. <@ Linkage > 5. <@ Definitions > * <@ Aggregate Types > @@ -168,8 +168,8 @@ The rationale is that a word can be signed or unsigned, so extending it to a long could be done in two ways, either by zero-extension, or by sign-extension. -- 3. Constants --------------- +- 3. Constants and Vals +----------------------- `bnf CONST := @@ -182,6 +182,10 @@ by zero-extension, or by sign-extension. CONST | 'thread' $IDENT # Thread-local symbol + VAL := + DYNCONST + | %IDENT + Constants come in two kinds: compile-time constants and dynamic constants. Dynamic constants include compile-time constants and other symbol variants that are only known at @@ -221,6 +225,10 @@ When the `thread` keyword prefixes a symbol name, the symbol's numeric value is resolved at runtime in the thread-local storage. +Vals are used as arguments in regular, phi, and jump +instructions within function definitions. They are +either constants or function-scope temporaries. + - 4. Linkage ------------ @@ -293,6 +301,15 @@ using linkage flags. '{' ( SUBTY [NUMBER] ), '}' + | # Union type + 'type' :IDENT '=' ['align' NUMBER] + '{' + ( + '{' + ( SUBTY [NUMBER] ), + '}' + )+ + '}' | # Opaque type 'type' :IDENT '=' 'align' NUMBER '{' NUMBER '}' @@ -318,6 +335,15 @@ explicitly specified by the programmer. type :cryptovector = align 16 { w 4 } +Union types allow the same chunk of memory to be used with +different layouts. They are defined by enclosing multiple +regular aggregate type bodies in a pair of curly braces. +Size and alignment of union types are set to the maximum size +and alignment of each variation or, in the case of alignment, +can be explicitly specified. + + type :un9 = { { b } { s } } + Opaque types are used when the inner structure of an aggregate cannot be specified; the alignment for opaque types is mandatory. They are defined simply by enclosing |