184 lines
8.0 KiB
C
184 lines
8.0 KiB
C
// Code to access multiple segments within gcc.
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//
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// Copyright (C) 2008 Kevin O'Connor <kevin@koconnor.net>
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//
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// This file may be distributed under the terms of the GNU LGPLv3 license.
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#ifndef __FARPTR_H
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#define __FARPTR_H
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#include "ioport.h" // insb
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// Dummy definitions used to make sure gcc understands dependencies
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// between SET_SEG and GET/READ/WRITE_SEG macros.
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extern u16 __segment_ES, __segment_CS, __segment_DS, __segment_SS;
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extern u16 __segment_FS, __segment_GS;
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// Low level macros for reading/writing memory via a segment selector.
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#define READ8_SEG(SEG, value, var) \
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__asm__("movb %%" #SEG ":%1, %b0" : "=Qi"(value) \
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: "m"(var), "m"(__segment_ ## SEG))
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#define READ16_SEG(SEG, value, var) \
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__asm__("movw %%" #SEG ":%1, %w0" : "=ri"(value) \
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: "m"(var), "m"(__segment_ ## SEG))
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#define READ32_SEG(SEG, value, var) \
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__asm__("movl %%" #SEG ":%1, %0" : "=ri"(value) \
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: "m"(var), "m"(__segment_ ## SEG))
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#define READ64_SEG(SEG, value, var) do { \
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union u64_u32_u *__w64_ptr = (union u64_u32_u *)&(value); \
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union u64_u32_u *__r64_ptr = (union u64_u32_u *)&(var); \
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READ32_SEG(SEG, __w64_ptr->hi, __r64_ptr->hi); \
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READ32_SEG(SEG, __w64_ptr->lo, __r64_ptr->lo); \
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} while (0)
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#define WRITE8_SEG(SEG, var, value) \
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__asm__("movb %b1, %%" #SEG ":%0" : "=m"(var) \
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: "Q"(value), "m"(__segment_ ## SEG))
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#define WRITE16_SEG(SEG, var, value) \
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__asm__("movw %w1, %%" #SEG ":%0" : "=m"(var) \
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: "r"(value), "m"(__segment_ ## SEG))
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#define WRITE32_SEG(SEG, var, value) \
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__asm__("movl %1, %%" #SEG ":%0" : "=m"(var) \
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: "r"(value), "m"(__segment_ ## SEG))
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#define WRITE64_SEG(SEG, var, value) do { \
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union u64_u32_u __value; \
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union u64_u32_u *__w64_ptr = (union u64_u32_u *)&(var); \
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__value.val = (value); \
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WRITE32_SEG(SEG, __w64_ptr->hi, __value.hi); \
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WRITE32_SEG(SEG, __w64_ptr->lo, __value.lo); \
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} while (0)
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// Low level macros for getting/setting a segment register.
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#define __SET_SEG(SEG, value) \
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__asm__("movw %w1, %%" #SEG : "=m"(__segment_ ## SEG) \
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: "r"(value))
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#define __GET_SEG(SEG) ({ \
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u16 __seg; \
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__asm__("movw %%" #SEG ", %w0" : "=r"(__seg) \
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: "m"(__segment_ ## SEG)); \
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__seg;})
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// Macros for automatically choosing the appropriate memory size
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// access method.
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extern void __force_link_error__unknown_type();
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#define __GET_VAR(seg, var) ({ \
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typeof(var) __val; \
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if (sizeof(__val) == 1) \
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READ8_SEG(seg, __val, var); \
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else if (sizeof(__val) == 2) \
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READ16_SEG(seg, __val, var); \
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else if (sizeof(__val) == 4) \
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READ32_SEG(seg, __val, var); \
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else if (sizeof(__val) == 8) \
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READ64_SEG(seg, __val, var); \
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else \
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__force_link_error__unknown_type(); \
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__val; })
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#define __SET_VAR(seg, var, val) do { \
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if (sizeof(var) == 1) \
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WRITE8_SEG(seg, var, (val)); \
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else if (sizeof(var) == 2) \
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WRITE16_SEG(seg, var, (val)); \
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else if (sizeof(var) == 4) \
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WRITE32_SEG(seg, var, (val)); \
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else if (sizeof(var) == 8) \
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WRITE64_SEG(seg, var, (val)); \
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else \
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__force_link_error__unknown_type(); \
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} while (0)
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// Macros for accessing a variable in another segment. (They
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// automatically update the %es segment and then make the appropriate
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// access.)
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#define __GET_FARVAR(seg, var) ({ \
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SET_SEG(ES, (seg)); \
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GET_VAR(ES, (var)); })
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#define __SET_FARVAR(seg, var, val) do { \
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typeof(var) __sfv_val = (val); \
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SET_SEG(ES, (seg)); \
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SET_VAR(ES, (var), __sfv_val); \
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} while (0)
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// Macros for accesssing a 32bit pointer from 16bit real mode. (They
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// automatically update the %es segment, break the pointer into
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// segment/offset, and then make the access.)
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#define __GET_FARPTR(ptr) ({ \
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typeof(&(ptr)) __ptr = &(ptr); \
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GET_FARVAR(FARPTR_TO_SEG(__ptr) \
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, *(typeof(__ptr))FARPTR_TO_OFFSET(__ptr)); })
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#define __SET_FARPTR(ptr, val) do { \
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typeof (&(ptr)) __ptr = &(ptr); \
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SET_FARVAR(FARPTR_TO_SEG(__ptr) \
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, *(typeof(__ptr))FARPTR_TO_OFFSET(__ptr) \
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, (val)); \
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} while (0)
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// Macros for converting to/from 32bit style pointers to their
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// equivalent 16bit segment/offset values.
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#define FARPTR_TO_SEG(p) (((u32)(p)) >> 4)
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#define FARPTR_TO_OFFSET(p) (((u32)(p)) & 0xf)
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#define MAKE_FARPTR(seg,off) ((void*)(((u32)(seg)<<4)+(u32)(off)))
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#if MODE16 == 1
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// Definitions when in 16 bit mode.
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#define GET_FARVAR(seg, var) __GET_FARVAR((seg), (var))
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#define SET_FARVAR(seg, var, val) __SET_FARVAR((seg), (var), (val))
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#define GET_VAR(seg, var) __GET_VAR(seg, (var))
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#define SET_VAR(seg, var, val) __SET_VAR(seg, (var), (val))
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#define SET_SEG(SEG, value) __SET_SEG(SEG, (value))
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#define GET_SEG(SEG) __GET_SEG(SEG)
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#define GET_FARPTR(ptr) __GET_FARPTR(ptr)
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#define SET_FARPTR(ptr, val) __SET_FARPTR((ptr), (val))
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static inline void insb_far(u16 port, void *farptr, u16 count) {
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SET_SEG(ES, FARPTR_TO_SEG(farptr));
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insb(port, (u8*)FARPTR_TO_OFFSET(farptr), count);
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}
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static inline void insw_far(u16 port, void *farptr, u16 count) {
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SET_SEG(ES, FARPTR_TO_SEG(farptr));
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insw(port, (u16*)FARPTR_TO_OFFSET(farptr), count);
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}
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static inline void insl_far(u16 port, void *farptr, u16 count) {
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SET_SEG(ES, FARPTR_TO_SEG(farptr));
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insl(port, (u32*)FARPTR_TO_OFFSET(farptr), count);
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}
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static inline void outsb_far(u16 port, void *farptr, u16 count) {
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SET_SEG(ES, FARPTR_TO_SEG(farptr));
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outsb(port, (u8*)FARPTR_TO_OFFSET(farptr), count);
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}
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static inline void outsw_far(u16 port, void *farptr, u16 count) {
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SET_SEG(ES, FARPTR_TO_SEG(farptr));
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outsw(port, (u16*)FARPTR_TO_OFFSET(farptr), count);
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}
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static inline void outsl_far(u16 port, void *farptr, u16 count) {
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SET_SEG(ES, FARPTR_TO_SEG(farptr));
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outsl(port, (u32*)FARPTR_TO_OFFSET(farptr), count);
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}
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#else
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// In 32-bit mode there is no need to mess with the segments.
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#define GET_FARVAR(seg, var) \
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(*((typeof(&(var)))MAKE_FARPTR((seg), (u32)&(var))))
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#define SET_FARVAR(seg, var, val) \
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do { GET_FARVAR((seg), (var)) = (val); } while (0)
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#define GET_VAR(seg, var) (var)
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#define SET_VAR(seg, var, val) do { (var) = (val); } while (0)
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#define SET_SEG(SEG, value) ((void)(value))
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#define GET_SEG(SEG) 0
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#define GET_FARPTR(ptr) (ptr)
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#define SET_FARPTR(ptr, val) do { (ptr) = (val); } while (0)
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#define insb_far(port, farptr, count) insb(port, farptr, count)
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#define insw_far(port, farptr, count) insw(port, farptr, count)
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#define insl_far(port, farptr, count) insl(port, farptr, count)
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#define outsb_far(port, farptr, count) outsb(port, farptr, count)
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#define outsw_far(port, farptr, count) outsw(port, farptr, count)
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#define outsl_far(port, farptr, count) outsl(port, farptr, count)
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#endif
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#endif // farptr.h
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