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https://github.com/cc65/cc65.git
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Added a .ORG keyword to ca65 structs/unions.
Allow 24-bit numbers as operands in ca65 structs/unions.
This commit is contained in:
Greg King
parent
3b128ba59f
commit
0896deedef
137
doc/ca65.sgml
137
doc/ca65.sgml
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@ -1,4 +1,4 @@
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<!doctype linuxdoc system> <!-- -*- text-mode -*- -->
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<!doctype linuxdoc system>
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<article>
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<title>ca65 Users Guide
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@ -1752,18 +1752,18 @@ either a string or an expression.
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<sect1><tt>.SIZEOF</tt><label id=".SIZEOF"><p>
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<tt/.SIZEOF/ is a pseudo function that returns the size of its argument. The
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argument can be a struct/union, a struct member, a procedure, or a label. In
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case of a procedure or label, its size is defined by the amount of data
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placed in the segment where the label is relative to. If a line of code
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switches segments (for example in a macro) data placed in other segments
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does not count for the size.
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<tt/.SIZEOF()/ is a pseudo function that returns the size of its argument.
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The argument can be a struct/union, a struct member, a scope/procedure, or a
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label. In the case of a procedure or label, its size is defined by the
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amount of data placed in the segment where the label is relative to. If a
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line of code switches segments (for example, in a macro), data placed in
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other segments does not count for the size.
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Please note that a symbol or scope must exist, before it is used together with
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<tt/.SIZEOF/ (this may get relaxed later, but will always be true for scopes).
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A scope has preference over a symbol with the same name, so if the last part
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of a name represents both, a scope and a symbol, the scope is chosen over the
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symbol.
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Please note that a symbol or scope must exist before it can be used together
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with <tt/.SIZEOF()/ (that may get relaxed later, but always will be true for
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scopes). A scope has preference over a symbol with the same name; so, if the
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last part of a name represents both a scope and a symbol, then the scope is
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chosen over the symbol.
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After the following code:
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@ -2496,7 +2496,7 @@ Here's a list of all control commands and a description, what they do:
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<sect1><tt>.ENDPROC</tt><label id=".ENDPROC"><p>
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End of local lexical level (see <tt><ref id=".PROC" name=".PROC"></tt>).
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End of the local lexical level (see <tt><ref id=".PROC" name=".PROC"></tt>).
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<sect1><tt>.ENDREP, .ENDREPEAT</tt><label id=".ENDREPEAT"><p>
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@ -2506,7 +2506,7 @@ Here's a list of all control commands and a description, what they do:
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<sect1><tt>.ENDSCOPE</tt><label id=".ENDSCOPE"><p>
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End of local lexical level (see <tt/<ref id=".SCOPE" name=".SCOPE">/).
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End of the local lexical level (see <tt/<ref id=".SCOPE" name=".SCOPE">/).
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<sect1><tt>.ENDSTRUCT</tt><label id=".ENDSTRUCT"><p>
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@ -2530,8 +2530,8 @@ Here's a list of all control commands and a description, what they do:
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otherwise the enumeration members are placed in the enclosing scope.
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In the enumeration body, symbols are declared. The first symbol has a value
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of zero, and each following symbol will get the value of the preceding plus
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one. This behaviour may be overridden by an explicit assignment. Two symbols
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of zero, and each following symbol will get the value of the preceding, plus
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one. That behaviour may be overridden by an explicit assignment. Two symbols
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may have the same value.
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Example:
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@ -2544,9 +2544,9 @@ Here's a list of all control commands and a description, what they do:
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.endenum
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</verb></tscreen>
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Above example will create a new scope named <tt/errorcodes/ with three
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symbols in it that get the values 0, 1 and 2 respectively. Another way
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to write this would have been:
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The above example will create a new scope named <tt/errorcodes/ with three
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symbols in it that get the values 0, 1, and 2 respectively. Another way
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to write that would have been:
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<tscreen><verb>
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.scope errorcodes
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@ -2575,12 +2575,12 @@ Here's a list of all control commands and a description, what they do:
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.endenum
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</verb></tscreen>
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In this example, the enumeration does not have a name, which means that the
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members will be visible in the enclosing scope and can be used in this scope
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In that example, the enumeration does not have a name, which means that the
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members will be visible in the enclosing scope, and can be used in that scope
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without explicit scoping. The first member (<tt/EUNKNOWN/) has the value -1.
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The value for the following members is incremented by one, so <tt/EOK/ would
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be zero and so on. <tt/EWOULDBLOCK/ is an alias for <tt/EGAIN/, so it has an
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override for the value using an already defined symbol.
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The values for the following members are incremented by one; so, <tt/EOK/
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would be zero, and so on. <tt/EWOULDBLOCK/ is an alias for <tt/EAGAIN/; so,
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it has an override for the value, using an already defined symbol.
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<sect1><tt>.ERROR</tt><label id=".ERROR"><p>
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@ -4672,22 +4672,22 @@ compiler, depending on the target system selected:
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</itemize>
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<sect>Structs and unions<label id="structs"><p>
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<sect1>Structs and unions Overview<p>
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Structs and unions are special forms of <ref id="scopes" name="scopes">. They
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are to some degree comparable to their C counterparts. Both have a list of
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members. Each member allocates storage and may optionally have a name, which,
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in case of a struct, is the offset from the beginning and, in case of a union,
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is always zero.
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are, to some degree, comparable to their C counterparts. Both have a list of
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members. Each member allocates storage, and optionally may have a name whose
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value, in the case of a struct, usually is the storage offset from the
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beginning, and in the case of a union, doesn't change, and usually is zero.
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<sect1>Declaration<p>
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Here is an example for a very simple struct with two members and a total size
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of 4 bytes:
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<tscreen><verb>
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.struct Point
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xcoord .word
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@ -4695,10 +4695,9 @@ of 4 bytes:
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.endstruct
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</verb></tscreen>
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A union shares the total space between all its members, its size is the same
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A union shares the total space between all its members; its size is the same
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as that of the largest member. The offset of all members relative to the union
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is zero.
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<tscreen><verb>
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.union Entry
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index .word
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@ -4706,13 +4705,12 @@ is zero.
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.endunion
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</verb></tscreen>
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A struct or union must not necessarily have a name. If it is anonymous, no
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local scope is opened, the identifiers used to name the members are placed
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A struct or union may not necessarily have a name. If it is anonymous, no
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local scope is opened; the identifiers used to name the members are placed
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into the current scope instead.
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A struct may contain unnamed members and definitions of local structs. The
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storage allocators may contain a multiplier, as in the example below:
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A struct may contain unnamed members and definitions of local structs/unions.
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The storage allocators may contain a multiplier, as in the example below:
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<tscreen><verb>
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.struct Circle
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.struct Point
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@ -4721,13 +4719,51 @@ storage allocators may contain a multiplier, as in the example below:
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Radius .word
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.endstruct
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</verb></tscreen>
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The size of the Circle struct is 6 (three words).
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<sect1>The storage allocator keywords<p>
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<descrip>
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<tag/.BYTE, .RES/
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Allocates multiples of 1 byte. <tt/.RES/ requires an operand.
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<tag/.DBYTE, .WORD, .ADDR/
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Allocates multiples of 2 bytes.
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<tag/.FARADDR/
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Allocates multiples of 3 bytes.
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<tag/.DWORD/
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Allocates multiples of 4 bytes.
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</descrip>
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<sect1>The <tt/.ORG/ keyword<p>
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The <tt/.ORG/ keyword changes the offset value that is assigned to subsequent
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member names. It's useful when using a struct to define the names of the
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registers in an I/O chip. Example:
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<tscreen><verb>
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; 6551
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.struct ACIA ; Asynchronous Communications Interface Adapter
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.org $031C
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DATA .byte
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STATUS .byte
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CMD .byte ; Command register
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CTRL .byte ; Control register
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.endstruct
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lda ACIA::DATA ; Get an RS-232 character
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</verb></tscreen>
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<sect1>The <tt/.TAG/ keyword<p>
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Using the <ref id=".TAG" name=".TAG"> keyword, it is possible to reserve space
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for an already defined struct or unions within another struct:
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By using the <ref id=".TAG" name=".TAG"> keyword, it is possible to reserve
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space for an already defined struct or union within another struct:
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<tscreen><verb>
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.struct Point
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xcoord .word
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@ -4740,33 +4776,30 @@ for an already defined struct or unions within another struct:
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.endstruct
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</verb></tscreen>
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Space for a struct or union may be allocated using the <ref id=".TAG"
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Actual space for a struct or union may be allocated by using the <ref id=".TAG"
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name=".TAG"> directive.
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<tscreen><verb>
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C: .tag Circle
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C: .tag Circle
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</verb></tscreen>
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Currently, members are just offsets from the start of the struct or union. To
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access a field of a struct, the member offset has to be added to the address
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of the struct itself:
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access a field of a struct, the member offset must be added to the address of
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the struct variable itself:
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<tscreen><verb>
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lda C+Circle::Radius ; Load circle radius into A
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</verb></tscreen>
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This may change in a future version of the assembler.
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That may change in a future version of the assembler.
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<sect1>Limitations<p>
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Structs and unions are currently implemented as nested symbol tables (in fact,
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Structs and unions currently are implemented as nested symbol tables (in fact,
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they were a by-product of the improved scoping rules). Currently, the
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assembler has no idea of types. This means that the <ref id=".TAG"
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name=".TAG"> keyword will only allocate space. You won't be able to initialize
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variables declared with <ref id=".TAG" name=".TAG">, and adding an embedded
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assembler has no idea of types. That means that the <ref id=".TAG"
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name=".TAG"> keyword only will allocate space. You won't be able to initialize
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variables declared with <ref id=".TAG" name=".TAG">; and, adding an embedded
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structure to another structure with <ref id=".TAG" name=".TAG"> will not make
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this structure accessible by using the '::' operator.
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that added structure accessible by using the '::' operator.
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@ -5,7 +5,6 @@
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/* .STRUCT/.UNION commands */
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/* */
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/* */
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/* */
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/* (C) 2003-2011, Ullrich von Bassewitz */
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/* Roemerstrasse 52 */
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/* D-70794 Filderstadt */
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static long Member (long AllocSize)
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/* Read one struct member and return its size */
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{
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long Multiplicator;
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long Multiplier;
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/* A multiplicator may follow */
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/* A multiplier may follow */
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if (CurTok.Tok != TOK_SEP) {
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Multiplicator = ConstExpression ();
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if (Multiplicator <= 0) {
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Multiplier = ConstExpression ();
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if (Multiplier <= 0) {
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ErrorSkip ("Range error");
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Multiplicator = 1;
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Multiplier = 1;
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}
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AllocSize *= Multiplicator;
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AllocSize *= Multiplier;
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}
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/* Check the size for a reasonable value */
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if (AllocSize >= 0x10000) {
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if (AllocSize >= 0x1000000) {
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ErrorSkip ("Range error");
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}
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@ -102,10 +101,11 @@ static long DoStructInternal (long Offs, unsigned Type)
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long Size = 0;
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/* Outside of other structs, we need a name. Inside another struct or
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** union, the struct may be anonymous, in which case no new lexical level
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** union, the struct may be anonymous; in which case, no new lexical level
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** is started.
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*/
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int Anon = (CurTok.Tok != TOK_IDENT);
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if (!Anon) {
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/* Enter a new scope, then skip the name */
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SymEnterLevel (&CurTok.SVal, SCOPE_STRUCT, ADDR_SIZE_ABS, 0);
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@ -121,7 +121,6 @@ static long DoStructInternal (long Offs, unsigned Type)
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while (CurTok.Tok != TOK_ENDSTRUCT &&
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CurTok.Tok != TOK_ENDUNION &&
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CurTok.Tok != TOK_EOF) {
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long MemberSize;
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SymTable* Struct;
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SymEntry* Sym;
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@ -132,14 +131,14 @@ static long DoStructInternal (long Offs, unsigned Type)
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continue;
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}
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/* The format is "[identifier] storage-allocator [, multiplicator]" */
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/* The format is "[identifier ].storage-allocator[ multiplier]" */
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Sym = 0;
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if (CurTok.Tok == TOK_IDENT) {
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/* Beware: An identifier may also be a macro, in which case we have
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** to start over.
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/* Beware: An identifier may be a macro also;
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** in which case, we must start over.
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*/
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Macro* M = FindMacro (&CurTok.SVal);
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if (M) {
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MacExpandStart (M);
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continue;
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@ -155,10 +154,9 @@ static long DoStructInternal (long Offs, unsigned Type)
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NextTok ();
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}
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/* Read storage allocators */
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MemberSize = 0; /* In case of errors, use zero */
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/* Read the storage allocator */
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MemberSize = 0; /* In case of errors or .ORG, use zero */
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switch (CurTok.Tok) {
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case TOK_BYTE:
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NextTok ();
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MemberSize = Member (1);
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@ -190,6 +188,15 @@ static long DoStructInternal (long Offs, unsigned Type)
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}
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break;
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case TOK_ORG:
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NextTok ();
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if (CurTok.Tok == TOK_SEP) {
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ErrorSkip ("Address is missing");
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} else {
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Offs = Member (1);
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}
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break;
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case TOK_TAG:
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NextTok ();
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Struct = ParseScopedSymTable ();
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@ -244,8 +251,8 @@ static long DoStructInternal (long Offs, unsigned Type)
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ConsumeSep ();
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}
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/* If this is not a anon struct, enter a special symbol named ".size"
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** into the symbol table of the struct that holds the size of the
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/* If this is not an anon. struct, enter a special symbol named ".size"
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** into the symbol table, of the struct, that holds the size of the
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** struct. Since the symbol starts with a dot, it cannot be accessed
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** by user code.
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** Leave the struct scope level.
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