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diff --git a/gc/doc/README.ews4800 b/gc/doc/README.ews4800 new file mode 100644 index 0000000..bced243 --- /dev/null +++ b/gc/doc/README.ews4800 @@ -0,0 +1,75 @@ +GC on EWS4800 +------------- + +1. About EWS4800 + EWS4800 is 32bit/64bit workstation. + + Vender: NEC Corporation + OS: UX/4800 R9.* - R13.* (SystemV R4.2) + CPU: R4000, R4400, R10000 (MIPS) + +2. Compiler + + 32bit: + Use ANSI C compiler. + CC = /usr/abiccs/bin/cc + + 64bit: + Use 64bit ANSI C compiler. + CC = /usr/ccs64/bin/cc + AR = /usr/ccs64/bin/ar + +3. ELF file format + *** Caution: The following infomation is empirical. *** + + 32bit: + ELF file has an unique format. (See a.out(4) and end(3C).) + + &_start + : text segment + &etext + DATASTART + : data segment (initialized) + &edata + DATASTART2 + : data segment (uninitialized) + &end + + Here, DATASTART and DATASTART2 are macros of GC, and are defined as + the following equations. (See include/private/gcconfig.h.) + The algorithm for DATASTART is similar with the function + GC_SysVGetDataStart() in os_dep.c. + + DATASTART = ((&etext + 0x3ffff) & ~0x3ffff) + (&etext & 0xffff) + + Dynamically linked: + DATASTART2 = (&_gp + 0x8000 + 0x3ffff) & ~0x3ffff + + Statically linked: + DATASTART2 = &edata + + GC has to check addresses both between DATASTART and &edata, and + between DATASTART2 and &end. If a program accesses between &etext + and DATASTART, or between &edata and DATASTART2, the segmentation + error occurs and the program stops. + + If a program is statically linked, there is not a gap between + &edata and DATASTART2. The global symbol &_DYNAMIC_LINKING is used + for the detection. + + 64bit: + ELF file has a simple format. (See end(3C).) + + _ftext + : text segment + _etext + _fdata = DATASTART + : data segment (initialized) + _edata + _fbss + : data segment (uninitialized) + _end = DATAEND + +-- +Hironori SAKAMOTO <hsaka@mth.biglobe.ne.jp> + |