mirror of
https://github.com/pnx/m16vm
synced 2026-06-16 03:44:55 +02:00
src/cpu.c: alot of refactoring, store state in a struct. and make vm.c "own" the state.
This commit is contained in:
parent
3db5f117d6
commit
6f60b1a74a
3 changed files with 120 additions and 73 deletions
113
src/cpu.c
113
src/cpu.c
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@ -31,9 +31,6 @@
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#include "syscall.h"
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#include "instr.h"
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// Registers r0, r15
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int16_t reg[CPU_NUM_REGS] = { 0 };
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/* Program */
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unsigned char *instr_mem = NULL;
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unsigned long instr_cnt = 0;
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@ -47,7 +44,7 @@ unsigned char cpu_flags = CPU_FLAGS_HALT;
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#define debug(...) fprintf(stderr, __VA_ARGS__)
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static void execute(struct instr *instr) {
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static void execute(struct cpu_state *state, struct instr *instr) {
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switch(instr->opcode) {
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case OP_NOOP :
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@ -56,128 +53,112 @@ static void execute(struct instr *instr) {
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break;
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case OP_ADD :
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debug("add\tr%i r%i r%i\n", instr->r.rs, instr->r.r0, instr->r.r1);
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reg[instr->r.rs] = reg[instr->r.r0] + reg[instr->r.r1];
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state->reg[instr->r.rs] = state->reg[instr->r.r0] + state->reg[instr->r.r1];
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break;
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case OP_MOVL :
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debug("movl\tr%i #%i\n", instr->i.rs, instr->i.imm);
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reg[instr->r.rs] = (reg[instr->r.rs] & 0xFF00) | instr->i.imm;
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state->reg[instr->r.rs] = (state->reg[instr->r.rs] & 0xFF00) | instr->i.imm;
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break;
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case OP_MOVH :
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debug("movh\tr%i #%i\n", instr->i.rs, instr->i.imm);
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reg[instr->r.rs] = (reg[instr->r.rs] & 0x00FF) | (((uint16_t) instr->i.imm) << 8);
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state->reg[instr->r.rs] = (state->reg[instr->r.rs] & 0x00FF) | (((uint16_t) instr->i.imm) << 8);
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break;
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case OP_LW :
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debug("lw\tr%i r%i #%i\n", instr->r.rs, instr->r.r0, instr->r.r1);
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reg[instr->r.rs] = mm_lw(reg[instr->r.r0] + instr->r.r1);
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state->reg[instr->r.rs] = mm_lw(state->reg[instr->r.r0] + instr->r.r1);
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break;
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case OP_SW :
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debug("sw\tr%i r%i #%i\n", instr->r.rs, instr->r.r0, instr->r.r1);
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mm_sw(reg[instr->r.rs] + instr->r.r1, reg[instr->r.r0]);
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mm_sw(state->reg[instr->r.rs] + instr->r.r1, state->reg[instr->r.r0]);
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break;
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case OP_JMP :
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debug("jmp\t#%i\n", instr->j.addr);
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cpu_set_pc(instr->j.addr);
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cpu_set_pc(state, instr->j.addr);
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break;
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case OP_JR :
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debug("jr\tr%i(#%i)\n", instr->i.rs, instr->i.imm);
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cpu_set_pc(reg[instr->r.rs] + instr->i.imm);
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cpu_set_pc(state, state->reg[instr->r.rs] + instr->i.imm);
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break;
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case OP_BEQ :
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debug("beq\tr%i r%i #%i\n", instr->ri.rs, instr->ri.r0, instr->ri.offset);
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// Compare rs, r0
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if (reg[instr->ri.rs] == reg[instr->ri.r0])
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cpu_set_pc(pc + instr->ri.offset);
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if (state->reg[instr->ri.rs] == state->reg[instr->ri.r0])
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cpu_set_pc(state, state->pc + instr->ri.offset);
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break;
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case OP_INT :
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debug("int %i(#%i)\n", instr->r.rs, instr->i.imm);
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vm_syscall(instr->i.rs, instr->i.imm, reg);
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vm_syscall(instr->i.rs, instr->i.imm, state->reg);
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break;
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default :
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fprintf(stderr, "Invalid instruction (%.2X)\n", instr->opcode);
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cpu_flags |= CPU_FLAGS_HALT;
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state->flags |= CPU_FLAGS_HALT;
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break;
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}
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}
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void print_memory() {
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void cpu_init(struct cpu_state *state)
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{
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state->pc = 0;
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state->flags = 0;
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memset(state->reg, 0, sizeof(state->reg[0]) * CPU_NUM_REGS);
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int i = 0;
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printf("\n");
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for(i = 0; i < 32; i++) {
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printf("%.2X ", memory[i]);
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}
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printf("\n");
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state->instr_mem = NULL;
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state->instr_cnt = 0;
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}
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void print_reg() {
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int i = 0;
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printf("\n");
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for(i = 0; i < 16; i++) {
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printf("r%i = %i\n", i, reg[i]);
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}
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printf("\n");
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}
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static unsigned char* instr_fetch() {
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if (pc + 1 >= instr_cnt >> 1)
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cpu_flags |= CPU_FLAGS_HALT;
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return instr_mem + (pc++ << 1);
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}
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int cpu_instr_load(void *ptr, unsigned len) {
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int cpu_instr_load(struct cpu_state *state, void *ptr, unsigned len) {
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if (len % 2) {
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fprintf(stderr, "Error: Instruction length must be a multiple of 2\n");
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return -1;
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}
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instr_mem = ptr;
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instr_cnt = len;
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state->instr_mem = ptr;
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state->instr_cnt = len;
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return len;
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}
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void cpu_instr_unload() {
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void cpu_instr_unload(struct cpu_state *state) {
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instr_mem = NULL;
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instr_cnt = 0;
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state->instr_mem = NULL;
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state->instr_cnt = 0;
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}
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void cpu_set_pc(uint16_t addr) {
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void cpu_set_pc(struct cpu_state *state, uint16_t addr) {
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if (addr > instr_cnt / 2) {
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fprintf(stderr, "Runtime error: Invalid instruction address %ui\n", addr);
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cpu_flags |= CPU_FLAGS_HALT;
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state->flags |= CPU_FLAGS_HALT;
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return;
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}
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pc = addr;
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state->pc = addr;
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}
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void cpu_run() {
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static unsigned char* instr_fetch(struct cpu_state *state) {
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mm_init();
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if (state->pc + 1 >= state->instr_cnt >> 1)
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state->flags |= CPU_FLAGS_HALT;
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cpu_flags &= ~CPU_FLAGS_HALT;
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return state->instr_mem + (state->pc++ << 1);
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}
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while(!(cpu_flags & CPU_FLAGS_HALT)) {
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struct instr instr;
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unsigned char* next = instr_fetch();
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int cpu_tick(struct cpu_state *state) {
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// decode instruction.
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instr_decode(next, &instr);
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struct instr instr;
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unsigned char* next;
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// Execute it.
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execute(&instr);
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if (state->flags & CPU_FLAGS_HALT) {
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return 1;
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}
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print_reg();
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print_memory();
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// Fetch next instruction
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next = instr_fetch(state);
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mm_exit();
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// decode instruction.
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instr_decode(next, &instr);
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// Execute it.
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execute(state, &instr);
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return 0;
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}
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27
src/cpu.h
27
src/cpu.h
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@ -25,12 +25,31 @@
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#define CPU_NUM_REGS 16
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int cpu_instr_load(void *ptr, unsigned len);
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#define CPU_FLAGS_HALT (1<<0)
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void cpu_instr_unload();
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struct cpu_state {
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// Registers r0, r15
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int16_t reg[CPU_NUM_REGS];
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void cpu_set_pc(uint16_t addr);
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// Program counter
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uint16_t pc;
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void cpu_run();
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// flags
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unsigned char flags;
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// Instruction
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unsigned char *instr_mem;
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unsigned long instr_cnt;
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};
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void cpu_init(struct cpu_state *state);
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int cpu_instr_load(struct cpu_state *state, void *ptr, unsigned len);
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void cpu_instr_unload(struct cpu_state *state);
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void cpu_set_pc(struct cpu_state *state, uint16_t addr);
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int cpu_tick(struct cpu_state *state);
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#endif /* CPU_H */
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53
src/vm.c
53
src/vm.c
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@ -25,8 +25,11 @@
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#include <fcntl.h>
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#include <errno.h>
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#include <unistd.h>
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#include "mm.h"
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#include "cpu.h"
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struct cpu_state state;
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// Load program from file
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unsigned long load_program(int fd, unsigned char **buf) {
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@ -46,8 +49,53 @@ unsigned long load_program(int fd, unsigned char **buf) {
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return rc;
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}
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void print_memory() {
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int i = 0;
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printf("\n");
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for(i = 0; i < 32; i++) {
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printf("%.2X ", memory[i]);
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}
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printf("\n");
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}
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void print_regs(uint16_t *regs) {
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int i = 0;
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printf("\n");
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for(i = 0; i < CPU_NUM_REGS; i++) {
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printf("r%i = %i\n", i, regs[i]);
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}
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printf("\n");
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}
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void run(unsigned char *instr_ptr, unsigned instr_len) {
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int rc;
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mm_init();
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cpu_init(&state);
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cpu_instr_load(&state, instr_ptr, instr_len);
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do {
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rc = cpu_tick(&state);
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} while(rc == 0);
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print_regs(state.reg);
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print_memory();
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mm_exit();
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}
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int main(int argc, char **argv) {
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int rc;
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int fd;
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unsigned char *instr_ptr;
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unsigned instr_len;
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@ -70,9 +118,8 @@ int main(int argc, char **argv) {
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if (instr_len < 0)
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return 1;
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cpu_instr_load(instr_ptr, instr_len);
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cpu_run();
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// Execute the program.
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run(instr_ptr, instr_len);
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if (instr_ptr)
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free(instr_ptr);
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