--- /dev/null
+// Code to access multiple segments within gcc.
+//
+// Copyright (C) 2008,2009 Kevin O'Connor <kevin@koconnor.net>
+//
+// This file may be distributed under the terms of the GNU LGPLv3 license.
+#ifndef __FARPTR_H
+#define __FARPTR_H
+
+#include "ioport.h" // insb
+
+// Dummy definitions used to make sure gcc understands dependencies
+// between SET_SEG and GET/READ/WRITE_SEG macros.
+extern u16 __segment_ES, __segment_CS, __segment_DS, __segment_SS;
+extern u16 __segment_FS, __segment_GS;
+
+// Low level macros for reading/writing memory via a segment selector.
+#define READ8_SEG(prefix, SEG, value, var) \
+ __asm__(prefix "movb %%" #SEG ":%1, %b0" : "=Qi"(value) \
+ : "m"(var), "m"(__segment_ ## SEG))
+#define READ16_SEG(prefix, SEG, value, var) \
+ __asm__(prefix "movw %%" #SEG ":%1, %w0" : "=ri"(value) \
+ : "m"(var), "m"(__segment_ ## SEG))
+#define READ32_SEG(prefix, SEG, value, var) \
+ __asm__(prefix "movl %%" #SEG ":%1, %0" : "=ri"(value) \
+ : "m"(var), "m"(__segment_ ## SEG))
+#define READ64_SEG(prefix, SEG, value, var) do { \
+ union u64_u32_u __value; \
+ union u64_u32_u *__r64_ptr = (union u64_u32_u *)&(var); \
+ READ32_SEG(prefix, SEG, __value.hi, __r64_ptr->hi); \
+ READ32_SEG(prefix, SEG, __value.lo, __r64_ptr->lo); \
+ *(u64*)&(value) = __value.val; \
+ } while (0)
+#define WRITE8_SEG(prefix, SEG, var, value) \
+ __asm__(prefix "movb %b1, %%" #SEG ":%0" : "=m"(var) \
+ : "Q"(value), "m"(__segment_ ## SEG))
+#define WRITE16_SEG(prefix, SEG, var, value) \
+ __asm__(prefix "movw %w1, %%" #SEG ":%0" : "=m"(var) \
+ : "r"(value), "m"(__segment_ ## SEG))
+#define WRITE32_SEG(prefix, SEG, var, value) \
+ __asm__(prefix "movl %1, %%" #SEG ":%0" : "=m"(var) \
+ : "r"(value), "m"(__segment_ ## SEG))
+#define WRITE64_SEG(prefix, SEG, var, value) do { \
+ union u64_u32_u __value; \
+ union u64_u32_u *__w64_ptr = (union u64_u32_u *)&(var); \
+ typeof(var) __value_tmp = (value); \
+ __value.val = *(u64*)&__value_tmp; \
+ WRITE32_SEG(prefix, SEG, __w64_ptr->hi, __value.hi); \
+ WRITE32_SEG(prefix, SEG, __w64_ptr->lo, __value.lo); \
+ } while (0)
+
+// Macros for automatically choosing the appropriate memory size
+// access method.
+extern void __force_link_error__unknown_type(void);
+
+#define __GET_VAR(prefix, seg, var) ({ \
+ typeof(var) __val; \
+ if (sizeof(__val) == 1) \
+ READ8_SEG(prefix, seg, __val, var); \
+ else if (sizeof(__val) == 2) \
+ READ16_SEG(prefix, seg, __val, var); \
+ else if (sizeof(__val) == 4) \
+ READ32_SEG(prefix, seg, __val, var); \
+ else if (sizeof(__val) == 8) \
+ READ64_SEG(prefix, seg, __val, var); \
+ else \
+ __force_link_error__unknown_type(); \
+ __val; })
+
+#define __SET_VAR(prefix, seg, var, val) do { \
+ if (sizeof(var) == 1) \
+ WRITE8_SEG(prefix, seg, var, (val)); \
+ else if (sizeof(var) == 2) \
+ WRITE16_SEG(prefix, seg, var, (val)); \
+ else if (sizeof(var) == 4) \
+ WRITE32_SEG(prefix, seg, var, (val)); \
+ else if (sizeof(var) == 8) \
+ WRITE64_SEG(prefix, seg, var, (val)); \
+ else \
+ __force_link_error__unknown_type(); \
+ } while (0)
+
+// Low level macros for getting/setting a segment register.
+#define __SET_SEG(SEG, value) \
+ __asm__("movw %w1, %%" #SEG : "=m"(__segment_ ## SEG) \
+ : "rm"(value))
+#define __GET_SEG(SEG) ({ \
+ u16 __seg; \
+ __asm__("movw %%" #SEG ", %w0" : "=rm"(__seg) \
+ : "m"(__segment_ ## SEG)); \
+ __seg;})
+
+// Macros for accessing a variable in another segment. (They
+// automatically update the %es segment and then make the appropriate
+// access.)
+#define __GET_FARVAR(seg, var) ({ \
+ SET_SEG(ES, (seg)); \
+ GET_VAR(ES, (var)); })
+#define __SET_FARVAR(seg, var, val) do { \
+ typeof(var) __sfv_val = (val); \
+ SET_SEG(ES, (seg)); \
+ SET_VAR(ES, (var), __sfv_val); \
+ } while (0)
+
+// Macros for accesssing a 32bit flat mode pointer from 16bit real
+// mode. (They automatically update the %es segment, break the
+// pointer into segment/offset, and then make the access.)
+#define __GET_FLATPTR(ptr) ({ \
+ typeof(&(ptr)) __ptr = &(ptr); \
+ GET_FARVAR(FLATPTR_TO_SEG(__ptr) \
+ , *(typeof(__ptr))FLATPTR_TO_OFFSET(__ptr)); })
+#define __SET_FLATPTR(ptr, val) do { \
+ typeof (&(ptr)) __ptr = &(ptr); \
+ SET_FARVAR(FLATPTR_TO_SEG(__ptr) \
+ , *(typeof(__ptr))FLATPTR_TO_OFFSET(__ptr) \
+ , (val)); \
+ } while (0)
+
+// Macros for converting to/from 32bit flat mode pointers to their
+// equivalent 16bit segment/offset values.
+#define FLATPTR_TO_SEG(p) (((u32)(p)) >> 4)
+#define FLATPTR_TO_OFFSET(p) (((u32)(p)) & 0xf)
+#define MAKE_FLATPTR(seg,off) ((void*)(((u32)(seg)<<4)+(u32)(off)))
+
+
+#if MODESEGMENT == 1
+
+// Definitions when using segmented mode.
+#define GET_FARVAR(seg, var) __GET_FARVAR((seg), (var))
+#define SET_FARVAR(seg, var, val) __SET_FARVAR((seg), (var), (val))
+#define GET_VAR(seg, var) __GET_VAR("", seg, (var))
+#define SET_VAR(seg, var, val) __SET_VAR("", seg, (var), (val))
+#define SET_SEG(SEG, value) __SET_SEG(SEG, (value))
+#define GET_SEG(SEG) __GET_SEG(SEG)
+#define GET_FLATPTR(ptr) __GET_FLATPTR(ptr)
+#define SET_FLATPTR(ptr, val) __SET_FLATPTR((ptr), (val))
+
+static inline void insb_fl(u16 port, void *ptr_fl, u16 count) {
+ SET_SEG(ES, FLATPTR_TO_SEG(ptr_fl));
+ insb(port, (u8*)FLATPTR_TO_OFFSET(ptr_fl), count);
+}
+static inline void insw_fl(u16 port, void *ptr_fl, u16 count) {
+ SET_SEG(ES, FLATPTR_TO_SEG(ptr_fl));
+ insw(port, (u16*)FLATPTR_TO_OFFSET(ptr_fl), count);
+}
+static inline void insl_fl(u16 port, void *ptr_fl, u16 count) {
+ SET_SEG(ES, FLATPTR_TO_SEG(ptr_fl));
+ insl(port, (u32*)FLATPTR_TO_OFFSET(ptr_fl), count);
+}
+static inline void outsb_fl(u16 port, void *ptr_fl, u16 count) {
+ SET_SEG(ES, FLATPTR_TO_SEG(ptr_fl));
+ outsb(port, (u8*)FLATPTR_TO_OFFSET(ptr_fl), count);
+}
+static inline void outsw_fl(u16 port, void *ptr_fl, u16 count) {
+ SET_SEG(ES, FLATPTR_TO_SEG(ptr_fl));
+ outsw(port, (u16*)FLATPTR_TO_OFFSET(ptr_fl), count);
+}
+static inline void outsl_fl(u16 port, void *ptr_fl, u16 count) {
+ SET_SEG(ES, FLATPTR_TO_SEG(ptr_fl));
+ outsl(port, (u32*)FLATPTR_TO_OFFSET(ptr_fl), count);
+}
+
+#else
+
+// In 32-bit flat mode there is no need to mess with the segments.
+#define GET_FARVAR(seg, var) \
+ (*((typeof(&(var)))MAKE_FLATPTR((seg), &(var))))
+#define SET_FARVAR(seg, var, val) \
+ do { GET_FARVAR((seg), (var)) = (val); } while (0)
+#define GET_VAR(seg, var) (var)
+#define SET_VAR(seg, var, val) do { (var) = (val); } while (0)
+#define SET_SEG(SEG, value) ((void)(value))
+#define GET_SEG(SEG) 0
+#define GET_FLATPTR(ptr) (ptr)
+#define SET_FLATPTR(ptr, val) do { (ptr) = (val); } while (0)
+
+#define insb_fl(port, ptr_fl, count) insb(port, ptr_fl, count)
+#define insw_fl(port, ptr_fl, count) insw(port, ptr_fl, count)
+#define insl_fl(port, ptr_fl, count) insl(port, ptr_fl, count)
+#define outsb_fl(port, ptr_fl, count) outsb(port, ptr_fl, count)
+#define outsw_fl(port, ptr_fl, count) outsw(port, ptr_fl, count)
+#define outsl_fl(port, ptr_fl, count) outsl(port, ptr_fl, count)
+
+#endif
+
+// Definition for common 16bit segment/offset pointers.
+struct segoff_s {
+ union {
+ struct {
+ u16 offset;
+ u16 seg;
+ };
+ u32 segoff;
+ };
+};
+#define SEGOFF(s,o) ({struct segoff_s __so; __so.offset=(o); __so.seg=(s); __so;})
+
+static inline struct segoff_s FLATPTR_TO_SEGOFF(void *p) {
+ return SEGOFF(FLATPTR_TO_SEG(p), FLATPTR_TO_OFFSET(p));
+}
+static inline void *SEGOFF_TO_FLATPTR(struct segoff_s so) {
+ return MAKE_FLATPTR(so.seg, so.offset);
+}
+
+#endif // farptr.h
