我想问的是@符合到底是什么意思?或哪里有@符号的详细解释,Thanks
是不是从某个地址开始的意思？
嗯,肯定是这意思,不过想知道关于@的详细说明,好像找到了,我用的是Codewarrior,手册上好像写了,我把贴上来 Global Variable Address Modifier (@address) You can assign global variables to specific addresses with the global variable address modifier. These variables are called 'absolute variables'. They are useful for accessing memory mapped I/O ports and have the following syntax: Declaration = <TypeSpec> <Declarator>[@<Address>|@"<Section>"] [= <Initializer>]; <TypeSpec> is the type specifier, e.g., int, char <Declarator> is the identifier of the global object, e.g., i, glob <Address> is the absolute address of the object, e.g., 0xff04, 0x00+8 <Initializer> is the value to which the global variable is initialized. A segment is created for each global object specified with an absolute address. This address must not be inside any address range in the SECTIONS entries of the link parameter file. Otherwise, there would be a linker error (overlapping segments). If the specified address has a size greater than that used for addressing the default data page, pointers pointing to this global variable must be "__far". An alternate way to assign global variables to specific addresses is (Listing 8.8). Listing 8.8 Assigning global variables to specific addresses #pragma DATA_SEG [__SHORT_SEG] <segment_name> setting the PLACEMENT section in the linker parameter file. An older method of accomplishing this is shown in Listing 8.9. Listing 8.9 Another means of assigning global variables to specific addresses <segment_name> INTO READ_ONLY <Address> ; Listing 8.10 is a correct and incorrect example of using the global variable address modifier and Listing 8.11 is a possible PRM file that corresponds with example Listing. Listing 8.10 Using the global variable address modifier //看这意思,就是把int型变量glob地址从0x0500开始,并把值10初始化时放在0x0500 int glob @0x0500 = 10; // OK, global variable "glob" is // at 0x0500, initialized with 10 void g() @0x40c0; // error (the object is a function) void f() { int i @0x40cc; // error (the object is a local variable) }
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