diff options
Diffstat (limited to 'src/farptr.h')
| -rw-r--r-- | src/farptr.h | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/src/farptr.h b/src/farptr.h new file mode 100644 index 0000000..1c3044b --- /dev/null +++ b/src/farptr.h @@ -0,0 +1,57 @@ +// Code to access multiple segments within gcc. +// +// Copyright (C) 2008 Kevin O'Connor <kevin@koconnor.net> +// +// This file may be distributed under the terms of the GNU GPLv3 license. + +#define READ8_SEG(SEG, var) ({ \ + u8 __value; \ + __asm__ __volatile__("movb %%" #SEG ":%1, %b0" \ + : "=Qi"(__value) : "m"(var)); \ + __value; }) +#define READ16_SEG(SEG, var) ({ \ + u16 __value; \ + __asm__ __volatile__("movw %%" #SEG ":%1, %w0" \ + : "=ri"(__value) : "m"(var)); \ + __value; }) +#define READ32_SEG(SEG, var) ({ \ + u32 __value; \ + __asm__ __volatile__("movl %%" #SEG ":%1, %0" \ + : "=ri"(__value) : "m"(var)); \ + __value; }) +#define WRITE8_SEG(SEG, var, value) \ + __asm__ __volatile__("movb %b0, %%" #SEG ":%1" \ + : : "Q"(value), "m"(var)) +#define WRITE16_SEG(SEG, var, value) \ + __asm__ __volatile__("movw %w0, %%" #SEG ":%1" \ + : : "r"(value), "m"(var)) +#define WRITE32_SEG(SEG, var, value) \ + __asm__ __volatile__("movl %0, %%" #SEG ":%1" \ + : : "r"(value), "m"(var)) + +#define GET_VAR(seg, var) ({ \ + typeof(var) __val; \ + if (__builtin_types_compatible_p(typeof(__val), u8)) \ + __val = READ8_SEG(seg, var); \ + else if (__builtin_types_compatible_p(typeof(__val), u16)) \ + __val = READ16_SEG(seg, var); \ + else if (__builtin_types_compatible_p(typeof(__val), u32)) \ + __val = READ32_SEG(seg, var); \ + __val; }) + +#define SET_VAR(seg, var, val) do { \ + if (__builtin_types_compatible_p(typeof(var), u8)) \ + WRITE8_SEG(seg, var, (val)); \ + else if (__builtin_types_compatible_p(typeof(var), u16)) \ + WRITE16_SEG(seg, var, (val)); \ + else if (__builtin_types_compatible_p(typeof(var), u32)) \ + WRITE32_SEG(seg, var, (val)); \ + } while (0) + +#define SET_SEG(SEG, value) \ + __asm__ __volatile__("movw %w0, %%" #SEG : : "r"(value)) +#define GET_SEG(SEG) ({ \ + u16 __seg; \ + __asm__ __volatile__("movw %%" #SEG ", %w0" : "=r"(__seg)); \ + __seg;}) + |