1 // Code to access multiple segments within gcc.
3 // Copyright (C) 2008 Kevin O'Connor <kevin@koconnor.net>
5 // This file may be distributed under the terms of the GNU GPLv3 license.
9 #include "ioport.h" // insb
11 // Dummy definitions used to make sure gcc understands dependencies
12 // between SET_SEG and GET/READ/WRITE_SEG macros.
13 extern u16 __segment_ES, __segment_CS, __segment_DS, __segment_SS;
15 // Low level macros for reading/writing memory via a segment selector.
16 #define READ8_SEG(SEG, var) ({ \
17 typeof(var) __value; \
18 __asm__("movb %%" #SEG ":%1, %b0" : "=Qi"(__value) \
19 : "m"(var), "m"(__segment_ ## SEG)); \
21 #define READ16_SEG(SEG, var) ({ \
22 typeof(var) __value; \
23 __asm__("movw %%" #SEG ":%1, %w0" : "=ri"(__value) \
24 : "m"(var), "m"(__segment_ ## SEG)); \
26 #define READ32_SEG(SEG, var) ({ \
27 typeof(var) __value; \
28 __asm__("movl %%" #SEG ":%1, %0" : "=ri"(__value) \
29 : "m"(var), "m"(__segment_ ## SEG)); \
31 #define READ64_SEG(SEG, var) ({ \
32 union u64_u32_u __value; \
33 union u64_u32_u *__r64_ptr = (union u64_u32_u *)&(var); \
34 __value.hi = READ32_SEG(SEG, __r64_ptr->hi); \
35 __value.lo = READ32_SEG(SEG, __r64_ptr->lo); \
37 #define WRITE8_SEG(SEG, var, value) \
38 __asm__("movb %b1, %%" #SEG ":%0" : "=m"(var) \
39 : "Q"(value), "m"(__segment_ ## SEG))
40 #define WRITE16_SEG(SEG, var, value) \
41 __asm__("movw %w1, %%" #SEG ":%0" : "=m"(var) \
42 : "r"(value), "m"(__segment_ ## SEG))
43 #define WRITE32_SEG(SEG, var, value) \
44 __asm__("movl %1, %%" #SEG ":%0" : "=m"(var) \
45 : "r"(value), "m"(__segment_ ## SEG))
46 #define WRITE64_SEG(SEG, var, value) do { \
47 union u64_u32_u __value; \
48 union u64_u32_u *__w64_ptr = (union u64_u32_u *)&(var); \
49 __value.val = (value); \
50 WRITE32_SEG(SEG, __w64_ptr->hi, __value.hi); \
51 WRITE32_SEG(SEG, __w64_ptr->lo, __value.lo); \
54 // Low level macros for getting/setting a segment register.
55 #define __SET_SEG(SEG, value) \
56 __asm__("movw %w1, %%" #SEG : "=m"(__segment_ ## SEG) \
58 #define __GET_SEG(SEG) ({ \
60 __asm__("movw %%" #SEG ", %w0" : "=r"(__seg) \
61 : "m"(__segment_ ## SEG)); \
64 // Macros for automatically choosing the appropriate memory size
66 extern void __force_link_error__unknown_type();
68 #define __GET_VAR(seg, var) ({ \
70 if (__builtin_types_compatible_p(typeof(__val), u8) \
71 || __builtin_types_compatible_p(typeof(__val), s8)) \
72 __val = READ8_SEG(seg, var); \
73 else if (__builtin_types_compatible_p(typeof(__val), u16) \
74 || __builtin_types_compatible_p(typeof(__val), s16)) \
75 __val = READ16_SEG(seg, var); \
76 else if (__builtin_types_compatible_p(typeof(__val), u32) \
77 || __builtin_types_compatible_p(typeof(__val), s32)) \
78 __val = READ32_SEG(seg, var); \
79 else if (__builtin_types_compatible_p(typeof(__val), u64) \
80 || __builtin_types_compatible_p(typeof(__val), s64)) \
81 __val = READ64_SEG(seg, var); \
83 __force_link_error__unknown_type(); \
86 #define __SET_VAR(seg, var, val) do { \
87 if (__builtin_types_compatible_p(typeof(var), u8) \
88 || __builtin_types_compatible_p(typeof(var), s8)) \
89 WRITE8_SEG(seg, var, (val)); \
90 else if (__builtin_types_compatible_p(typeof(var), u16) \
91 || __builtin_types_compatible_p(typeof(var), s16)) \
92 WRITE16_SEG(seg, var, (val)); \
93 else if (__builtin_types_compatible_p(typeof(var), u32) \
94 || __builtin_types_compatible_p(typeof(var), s32)) \
95 WRITE32_SEG(seg, var, (val)); \
96 else if (__builtin_types_compatible_p(typeof(var), u64) \
97 || __builtin_types_compatible_p(typeof(var), s64)) \
98 WRITE64_SEG(seg, var, (val)); \
100 __force_link_error__unknown_type(); \
103 // Macros for accessing a variable in another segment. (They
104 // automatically update the %es segment and then make the appropriate
106 #define __GET_FARVAR(seg, var) ({ \
107 SET_SEG(ES, (seg)); \
108 GET_VAR(ES, (var)); })
109 #define __SET_FARVAR(seg, var, val) do { \
110 typeof(var) __sfv_val = (val); \
111 SET_SEG(ES, (seg)); \
112 SET_VAR(ES, (var), __sfv_val); \
115 // Macros for accesssing a 32bit pointer from 16bit mode. (They
116 // automatically update the %es segment, break the pointer into
117 // segment/offset, and then make the access.)
118 #define __GET_FARPTR(ptr) ({ \
119 typeof(&(ptr)) __ptr = &(ptr); \
120 GET_FARVAR(FARPTR_TO_SEG(__ptr) \
121 , *(typeof(__ptr))FARPTR_TO_OFFSET(__ptr)); })
122 #define __SET_FARPTR(ptr, val) do { \
123 typeof (&(ptr)) __ptr = &(ptr); \
124 SET_FARVAR(FARPTR_TO_SEG(__ptr) \
125 , *(typeof(__ptr))FARPTR_TO_OFFSET(__ptr) \
129 // Macros for converting to/from 32bit style pointers to their
130 // equivalent 16bit segment/offset values.
131 #define FARPTR_TO_SEG(p) (((u32)(p)) >> 4)
132 #define FARPTR_TO_OFFSET(p) (((u32)(p)) & 0xf)
133 #define MAKE_FARPTR(seg,off) ((void*)(((seg)<<4)+(off)))
138 // Definitions when in 16 bit mode.
139 #define GET_FARVAR(seg, var) __GET_FARVAR((seg), (var))
140 #define SET_FARVAR(seg, var, val) __SET_FARVAR((seg), (var), (val))
141 #define GET_VAR(seg, var) __GET_VAR(seg, (var))
142 #define SET_VAR(seg, var, val) __SET_VAR(seg, (var), (val))
143 #define SET_SEG(SEG, value) __SET_SEG(SEG, (value))
144 #define GET_SEG(SEG) __GET_SEG(SEG)
145 #define GET_FARPTR(ptr) __GET_FARPTR(ptr)
146 #define SET_FARPTR(ptr, val) __SET_FARPTR((ptr), (val))
148 static inline void insb_far(u16 port, void *farptr, u16 count) {
149 SET_SEG(ES, FARPTR_TO_SEG(farptr));
150 insb(port, (u8*)FARPTR_TO_OFFSET(farptr), count);
152 static inline void insw_far(u16 port, void *farptr, u16 count) {
153 SET_SEG(ES, FARPTR_TO_SEG(farptr));
154 insw(port, (u16*)FARPTR_TO_OFFSET(farptr), count);
156 static inline void insl_far(u16 port, void *farptr, u16 count) {
157 SET_SEG(ES, FARPTR_TO_SEG(farptr));
158 insl(port, (u32*)FARPTR_TO_OFFSET(farptr), count);
160 static inline void outsb_far(u16 port, void *farptr, u16 count) {
161 SET_SEG(ES, FARPTR_TO_SEG(farptr));
162 outsb(port, (u8*)FARPTR_TO_OFFSET(farptr), count);
164 static inline void outsw_far(u16 port, void *farptr, u16 count) {
165 SET_SEG(ES, FARPTR_TO_SEG(farptr));
166 outsw(port, (u16*)FARPTR_TO_OFFSET(farptr), count);
168 static inline void outsl_far(u16 port, void *farptr, u16 count) {
169 SET_SEG(ES, FARPTR_TO_SEG(farptr));
170 outsl(port, (u32*)FARPTR_TO_OFFSET(farptr), count);
175 // In 32-bit mode there is no need to mess with the segments.
176 #define GET_FARVAR(seg, var) \
177 (*((typeof(&(var)))MAKE_FARPTR((seg), (u32)&(var))))
178 #define SET_FARVAR(seg, var, val) \
179 do { GET_FARVAR((seg), (var)) = (val); } while (0)
180 #define GET_VAR(seg, var) (var)
181 #define SET_VAR(seg, var, val) do { (var) = (val); } while (0)
182 #define SET_SEG(SEG, value) ((void)(value))
183 #define GET_SEG(SEG) 0
184 #define GET_FARPTR(ptr) (ptr)
185 #define SET_FARPTR(ptr, val) do { (ptr) = (val); } while (0)
187 #define insb_far(port, farptr, count) insb(port, farptr, count)
188 #define insw_far(port, farptr, count) insw(port, farptr, count)
189 #define insl_far(port, farptr, count) insl(port, farptr, count)
190 #define outsb_far(port, farptr, count) outsb(port, farptr, count)
191 #define outsw_far(port, farptr, count) outsw(port, farptr, count)
192 #define outsl_far(port, farptr, count) outsl(port, farptr, count)