Xv6 with picoc & Linkage editor: include/PIC.h Source File

00001 #ifndef __I386_PIC_H__
00002 #define __I386_PIC_H__
00003 #ifdef __DYN_LIB
00004 
00005 #undef __i686
00006 
00007 #if 1
00008 /* don't trash the athlon return stack */
00009 #if (__GNUC__ >= 3)     // FIXME: how do I check for the binutils version ?
00010 .section .gnu.linkonce.t.__i686.get_pc_thunk.bx,"ax",@progbits
00011 .global __i686.get_pc_thunk.bx
00012 .hidden __i686.get_pc_thunk.bx
00013 .type   __i686.get_pc_thunk.bx,@function
00014 __i686.get_pc_thunk.bx:
00015         movl    (%esp), %ebx
00016         ret
00017 .previous
00018 
00019 .macro PIC_INIT
00020         call    __i686.get_pc_thunk.bx
00021         addl    $_GLOBAL_OFFSET_TABLE_, %ebx
00022 .endm
00023 #else
00024 .text
00025 .Lgetpic:
00026         mov     (%esp),%ebx
00027         ret
00028 
00029 .macro PIC_INIT
00030         call    .Lgetpic
00031         addl    $_GLOBAL_OFFSET_TABLE_, %ebx
00032 .endm
00033 #endif
00034 #else
00035 /* standard code for PIC init */
00036 .macro PIC_INIT
00037         call    0f
00038 0:      popl    %ebx
00039         addl    $_GLOBAL_OFFSET_TABLE_+[.-0b], %ebx
00040 .endm
00041 #endif
00042 
00043 #define PIC_SAVE        pushl   %ebx
00044 #define PIC_RESTORE     popl    %ebx
00045 
00046 
00047 /* get memory variable (var) in register (reg) */
00048 .macro GET_VAR var reg
00049         movl    \var@GOT(%ebx), \reg
00050         movl    (\reg), \reg
00051 .endm
00052 
00053 /* put register (reg) into memory variable (var) TRASH register (tmp) */
00054 .macro PUT_VAR reg var tmp
00055         movl    \var@GOT(%ebx), \tmp
00056         movl    \reg, (\tmp)
00057 .endm
00058 
00059 /* get memory variable (var) in register (reg)
00060  * IF no more PIC-code is needed */
00061 .macro GET_1VAR var reg
00062         PIC_SAVE
00063         PIC_INIT
00064         GET_VAR \var, \reg
00065         PIC_RESTORE
00066 .endm
00067 
00068 /* put register (reg) into memory variable (var)
00069  * IF no more PIC-code is needed */
00070 .macro PUT_1VAR reg var
00071         PIC_SAVE
00072         PIC_INIT
00073         PUT_VAR \reg, \var, %ebx
00074         PIC_RESTORE
00075 .endm
00076 
00077 #else
00078 
00079 #define PIC_SAVE
00080 #define PIC_RESTORE
00081 #define PIC_INIT
00082 
00083 .macro GET_VAR var reg
00084         movl    \var, \reg
00085 .endm
00086 
00087 .macro PUT_VAR reg var tmp
00088         movl    \reg, \var
00089 .endm
00090 
00091 .macro GET_1VAR var reg
00092         GET_VAR \var, \reg
00093 .endm
00094 
00095 .macro PUT_1VAR reg var
00096         PUT_VAR \reg, \var, none
00097 .endm
00098 
00099 #endif
00100 #endif