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perfaware/part1: Remove unused defns, tidy up code

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doyle 2023-03-08 23:41:33 +11:00 committed by committed-name
parent d7b6598b1c
commit 68486e8855
1 changed files with 120 additions and 97 deletions
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217
part1/sim8086.c
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@ -7,31 +7,8 @@
#include <stdarg.h>
#include <stdbool.h>
typedef struct S86_Buffer S86_Buffer;
struct S86_Buffer {
char *data;
size_t size;
};
typedef struct S86_Str8 S86_Str8;
struct S86_Str8 {
char *data;
size_t size;
};
typedef struct S86_Globals S86_Globals;
struct S86_Globals {
HANDLE stdout_handle;
bool write_to_console;
};
typedef struct S86_BufferIterator {
S86_Buffer buffer;
size_t index;
} S86_BufferIterator;
S86_Globals s86_globals;
// NOTE: Macros
// ============================================================================
#define S86_STRINGIFY2(token) #token
#define S86_STRINGIFY(token) S86_STRINGIFY2(token)
#define S86_ASSERT(expr) \
@ -41,9 +18,38 @@ S86_Globals s86_globals;
} \
#define S86_ARRAY_UCOUNT(array) sizeof((array)) / sizeof((array)[0])
#define S86_CAST(Type) (Type)
// NOTE: Globals
// ============================================================================
typedef struct S86_Globals {
HANDLE stdout_handle;
bool write_to_console;
} S86_Globals;
S86_Globals s86_globals;
// NOTE: Strings
// ============================================================================
typedef struct S86_Str8 {
char *data;
size_t size;
} S86_Str8;
#define S86_STR8(string) (S86_Str8){.data = (string), .size = S86_ARRAY_UCOUNT(string) - 1 }
#define S86_STR8_FMT(string) (int)((string).size), (string).data
#define S86_CAST(Type) (Type)
// NOTE: Buffer
// ============================================================================
typedef struct S86_Buffer {
char *data;
size_t size;
} S86_Buffer;
typedef struct S86_BufferIterator {
S86_Buffer buffer;
size_t index;
} S86_BufferIterator;
bool S86_BufferIsValid(S86_Buffer buffer);
S86_BufferIterator S86_BufferIteratorInit(S86_Buffer buffer);
@ -51,11 +57,82 @@ bool S86_BufferIteratorHasMoreBytes(S86_BufferIterator it);
uint8_t S86_BufferIteratorPeekByte(S86_BufferIterator it);
uint8_t S86_BufferIteratorNextByte(S86_BufferIterator *it);
// NOTE: File
// ============================================================================
S86_Buffer S86_FileRead(char const *file_path);
void S86_FileFree(S86_Buffer buffer);
// NOTE: Print
// ============================================================================
void S86_PrintLn(S86_Str8 string);
void S86_PrintLnFmt(char const *fmt, ...);
// NOTE: Sim8086
// ============================================================================
typedef enum S86_InstructionType {
S86_InstructionType_MOVRegOrMemToOrFromReg,
S86_InstructionType_MOVImmediateToRegOrMem,
S86_InstructionType_MOVImmediateToReg,
S86_InstructionType_MOVMemToAccum,
S86_InstructionType_MOVAccumToMem,
S86_InstructionType_MOVRegOrMemToSegReg,
S86_InstructionType_MOVSegRegToRegOrMem,
S86_InstructionType_Count,
} S86_InstructionType;
/// Bit patterns and masks for decoding 8086 assembly. 8086 opcodes can be up
/// to 2 bytes long and mixed with instruction specific control bits. These
/// masks isolate the opcode bits from the bits can be checked after masking
/// the binary instruction stream.
///
/// Instructions that do not have opcode bits in the 2nd byte will have the mask
/// set to 0.
typedef struct S86_Instruction {
uint8_t op_mask0;
uint8_t op_bits0;
uint8_t op_mask1;
uint8_t op_bits1;
} S86_Instruction;
S86_Instruction const S86_INSTRUCTIONS[S86_InstructionType_Count] = {
[S86_InstructionType_MOVRegOrMemToOrFromReg] = {.op_mask0 = 0b1111'1100,
.op_bits0 = 0b1000'1000,
.op_mask1 = 0b0000'0000,
.op_bits1 = 0b0000'0000},
[S86_InstructionType_MOVImmediateToRegOrMem] = {.op_mask0 = 0b1111'1110,
.op_bits0 = 0b1100'0110,
.op_mask1 = 0b0011'1000,
.op_bits1 = 0b0000'0000},
[S86_InstructionType_MOVImmediateToReg] = {.op_mask0 = 0b1111'0000,
.op_bits0 = 0b1011'0000,
.op_mask1 = 0b0000'0000,
.op_bits1 = 0b0000'0000},
[S86_InstructionType_MOVMemToAccum] = {.op_mask0 = 0b1111'1110,
.op_bits0 = 0b1010'0000,
.op_mask1 = 0b0000'0000,
.op_bits1 = 0b0000'0000},
[S86_InstructionType_MOVAccumToMem] = {.op_mask0 = 0b1111'1110,
.op_bits0 = 0b1010'0010,
.op_mask1 = 0b0000'0000,
.op_bits1 = 0b0000'0000},
[S86_InstructionType_MOVRegOrMemToSegReg] = {.op_mask0 = 0b1111'1111,
.op_bits0 = 0b1000'1110,
.op_mask1 = 0b0010'0000,
.op_bits1 = 0b0000'0000},
[S86_InstructionType_MOVSegRegToRegOrMem] = {.op_mask0 = 0b1111'1111,
.op_bits0 = 0b1000'1100,
.op_mask1 = 0b0010'0000,
.op_bits1 = 0b0000'0000},
};
// NOTE: Implementation
// ============================================================================
bool S86_BufferIsValid(S86_Buffer buffer)
{
bool result = buffer.data && buffer.size;
@ -208,76 +285,25 @@ void S86_PrintLnFmt(char const *fmt, ...)
va_end(args);
}
typedef enum S86_ModEncoding S86_ModEncoding;
enum S86_ModEncoding {
S86_ModEncoding_MemModeNoDisplace = 0b00,
S86_ModEncoding_MemMode8 = 0b01,
S86_ModEncoding_MemMode16 = 0b10,
S86_ModEncoding_RegisterMode = 0b11,
};
typedef enum S86_InstructionType S86_InstructionType;
enum S86_InstructionType {
S86_InstructionType_MOVRegOrMemToOrFromReg,
S86_InstructionType_MOVImmediateToRegOrMem,
S86_InstructionType_MOVImmediateToReg,
S86_InstructionType_MOVMemToAccum,
S86_InstructionType_MOVAccumToMem,
S86_InstructionType_MOVRegOrMemToSegReg,
S86_InstructionType_MOVSegRegToRegOrMem,
S86_InstructionType_Count,
};
typedef struct S86_Instruction S86_Instruction;
struct S86_Instruction {
uint8_t op_mask0;
uint8_t op_bits0;
uint8_t op_mask1;
uint8_t op_bits1;
} S86_INSTRUCTIONS[S86_InstructionType_Count] = {
[S86_InstructionType_MOVRegOrMemToOrFromReg] = {.op_mask0 = 0b1111'1100,
.op_bits0 = 0b1000'1000,
.op_mask1 = 0b0000'0000,
.op_bits1 = 0b0000'0000},
[S86_InstructionType_MOVImmediateToRegOrMem] = {.op_mask0 = 0b1111'1110,
.op_bits0 = 0b1100'0110,
.op_mask1 = 0b0011'1000,
.op_bits1 = 0b0000'0000},
[S86_InstructionType_MOVImmediateToReg] = {.op_mask0 = 0b1111'0000,
.op_bits0 = 0b1011'0000,
.op_mask1 = 0b0000'0000,
.op_bits1 = 0b0000'0000},
[S86_InstructionType_MOVMemToAccum] = {.op_mask0 = 0b1111'1110,
.op_bits0 = 0b1010'0000,
.op_mask1 = 0b0000'0000,
.op_bits1 = 0b0000'0000},
[S86_InstructionType_MOVAccumToMem] = {.op_mask0 = 0b1111'1110,
.op_bits0 = 0b1010'0010,
.op_mask1 = 0b0000'0000,
.op_bits1 = 0b0000'0000},
[S86_InstructionType_MOVRegOrMemToSegReg] = {.op_mask0 = 0b1111'1111,
.op_bits0 = 0b1000'1110,
.op_mask1 = 0b0010'0000,
.op_bits1 = 0b0000'0000},
[S86_InstructionType_MOVSegRegToRegOrMem] = {.op_mask0 = 0b1111'1111,
.op_bits0 = 0b1000'1100,
.op_mask1 = 0b0010'0000,
.op_bits1 = 0b0000'0000},
};
int main(int argc, char **argv)
{
// NOTE: Argument handling
// =========================================================================
if (argc != 2) {
S86_PrintLn(S86_STR8("usage: sim8086.exe <binary asm file>"));
return -1;
}
char const *file_path = argv[1];
S86_Buffer buffer = S86_FileRead(file_path);
if (!S86_BufferIsValid(buffer)) {
S86_PrintLnFmt("File read failed [path=\"%s\"]", argv[1], buffer.size);
return -1;
}
// NOTE: Sim8086
// =========================================================================
// Mapping from a 'reg' encoding to the register name.
S86_Str8 const REGISTER_FIELD_ENCODING[2][8] = {
[0b0] =
{
@ -303,13 +329,8 @@ int main(int argc, char **argv)
},
};
char const *file_path = argv[1];
S86_Buffer buffer = S86_FileRead(file_path);
if (!S86_BufferIsValid(buffer)) {
S86_PrintLnFmt("File read failed [path=\"%s\"]", argv[1], buffer.size);
return -1;
}
// NOTE: Decode assembly
// =========================================================================
S86_PrintLn(S86_STR8("bits 16"));
S86_BufferIterator buffer_it = S86_BufferIteratorInit(buffer);
while (S86_BufferIteratorHasMoreBytes(buffer_it)) {
@ -326,7 +347,7 @@ int main(int argc, char **argv)
instruction_type == S86_InstructionType_Count && instruction_index < S86_ARRAY_UCOUNT(S86_INSTRUCTIONS);
instruction_index++)
{
S86_Instruction *item = S86_INSTRUCTIONS + instruction_index;
S86_Instruction const *item = S86_INSTRUCTIONS + instruction_index;
// NOTE: Check first instruction byte
// =================================================================
@ -354,7 +375,9 @@ int main(int argc, char **argv)
// =================================================================
S86_ASSERT(op_code_size > 0 && op_code_size <= S86_ARRAY_UCOUNT(op_code_bytes));
S86_ASSERT(instruction_type != S86_InstructionType_Count && "Unknown instruction");
switch (instruction_type) {
case S86_InstructionType_MOVRegOrMemToOrFromReg: {
// NOTE: Instruction does not have opcode bits in the 2nd byte
S86_ASSERT(op_code_size == 1);