Erick
58 lines
1.3 KiB
C
58 lines
1.3 KiB
C
/*
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TVM is a virtual machine for LC-3 based operating systems and it used for educational purposes.
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Open-source software under MIT License
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Written by Erick Ahmed, 2022
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*/
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#include <stdint.h>>
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/* Initializing 128kb of memory */
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uint16_t memory[UINT16_MAX];
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/* Initializing 10 registers of which:
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8 general purpose, 1 program counter, 1 conditional */
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enum {
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RG_GP0 = 0,
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RG_GP1,
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RG_GP2,
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RG_GP3,
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RG_GP4,
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RG_GP5,
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RG_GP6,
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RG_GP7,
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RG_PC = 0, // program counter
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RG_COND, // condition flag
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RG_COUNT
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};
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uint16_t reg[RG_COUNT];
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/* Creating instruction set opcodes */
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enum {
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OP_BR = 0, // branch
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OP_ADD, // add
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OP_LD, // load
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OP_ST, // store
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OP_JSR, // jump register
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OP_AND, // bitwise add
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OP_LDR, // load register
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OP_STR, // store register
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OP_RTI, // unused opcode
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OP_NOT, // bitwise not
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OP_LDI, // indirect load
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OP_STI, // indirect store
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OP_JMP, // jump
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OP_RES, // reserved opcode
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OP_LEA, // load effective address
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OP_TRAP, // execute trap
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};
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/* Creating condition flags */
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enum {
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FL_POS = 1, // P
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FL_ZRO = 1 << 1, // Z
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FL_NEG = 1 << 2, // N
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}
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