cosmopolitan/tool/build/lib/endian.h
Justine Tunney f4f4caab0e Add x86_64-linux-gnu emulator
I wanted a tiny scriptable meltdown proof way to run userspace programs
and visualize how program execution impacts memory. It helps to explain
how things like Actually Portable Executable works. It can show you how
the GCC generated code is going about manipulating matrices and more. I
didn't feel fully comfortable with Qemu and Bochs because I'm not smart
enough to understand them. I wanted something like gVisor but with much
stronger levels of assurances. I wanted a single binary that'll run, on
all major operating systems with an embedded GPL barrier ZIP filesystem
that is tiny enough to transpile to JavaScript and run in browsers too.

https://justine.storage.googleapis.com/emulator625.mp4
2020-08-25 04:43:42 -07:00

115 lines
2.7 KiB
C

#ifndef COSMOPOLITAN_TOOL_BUILD_LIB_ENDIAN_H_
#define COSMOPOLITAN_TOOL_BUILD_LIB_ENDIAN_H_
#include "libc/str/str.h"
#if !(__ASSEMBLER__ + __LINKER__ + 0)
#if __BYTE_ORDER__ + 0 == 1234
#define Read8(P) \
({ \
uint8_t *Ptr = (P); \
*Ptr; \
})
#define Read16(P) \
({ \
uint16_t Res; \
uint8_t *Ptr = (P); \
memcpy(&Res, Ptr, 2); \
Res; \
})
#define Read32(P) \
({ \
uint32_t Res; \
uint8_t *Ptr = (P); \
memcpy(&Res, Ptr, 4); \
Res; \
})
#define Read64(P) \
({ \
uint64_t Res; \
uint8_t *Ptr = (P); \
memcpy(&Res, Ptr, 8); \
Res; \
})
#define Write8(P, B) \
do { \
uint8_t *Ptr = (P); \
*Ptr = (B); \
} while (0)
#define Write16(P, V) \
do { \
uint16_t Val = (V); \
uint8_t *Ptr = (P); \
memcpy(Ptr, &Val, 2); \
} while (0)
#define Write32(P, V) \
do { \
uint32_t Val = (V); \
uint8_t *Ptr = (P); \
memcpy(Ptr, &Val, 4); \
} while (0)
#define Write64(P, V) \
do { \
uint64_t Val = (V); \
uint8_t *Ptr = (P); \
memcpy(Ptr, &Val, 8); \
} while (0)
#else
forceinline uint16_t Read8(const uint8_t p[hasatleast 1]) {
return p[0];
}
forceinline uint16_t Read16(const uint8_t p[hasatleast 2]) {
return p[0] | p[1] << 010;
}
forceinline uint32_t Read32(const uint8_t bytes[hasatleast 4]) {
return (uint32_t)bytes[0] << 000 | (uint32_t)bytes[1] << 010 |
(uint32_t)bytes[2] << 020 | (uint32_t)bytes[3] << 030;
}
forceinline uint64_t Read64(const uint8_t bytes[hasatleast 8]) {
return (uint64_t)bytes[0] << 000 | (uint64_t)bytes[1] << 010 |
(uint64_t)bytes[2] << 020 | (uint64_t)bytes[3] << 030 |
(uint64_t)bytes[4] << 040 | (uint64_t)bytes[5] << 050 |
(uint64_t)bytes[6] << 060 | (uint64_t)bytes[7] << 070;
}
forceinline void Write8(unsigned char p[hasatleast 1], uint8_t x) {
p[0] = x >> 000;
}
forceinline void Write16(unsigned char p[hasatleast 2], uint16_t x) {
p[0] = x >> 000;
p[1] = x >> 010;
}
forceinline void Write32(unsigned char p[hasatleast 4], uint64_t x) {
p[0] = x >> 000;
p[1] = x >> 010;
p[2] = x >> 020;
p[3] = x >> 030;
}
forceinline void Write64(unsigned char p[hasatleast 8], uint64_t x) {
p[0] = x >> 000;
p[1] = x >> 010;
p[2] = x >> 020;
p[3] = x >> 030;
p[4] = x >> 040;
p[5] = x >> 050;
p[6] = x >> 060;
p[7] = x >> 070;
}
#endif /* ENDIAN */
#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
#endif /* COSMOPOLITAN_TOOL_BUILD_LIB_ENDIAN_H_ */