86Box/src/codegen_new/codegen_backend_x86_ops_helpers.h

#define JMP_LEN_BYTES 5

static inline void codegen_addbyte(codeblock_t *block, uint8_t val)
{
        if (block_pos >= BLOCK_MAX)
                fatal("codegen_addbyte over! %i\n", block_pos);
        block_write_data[block_pos++] = val;
}
static inline void codegen_addbyte2(codeblock_t *block, uint8_t vala, uint8_t valb)
{
        if (block_pos > (BLOCK_MAX-2))
                fatal("codegen_addbyte2 over! %i\n", block_pos);
        block_write_data[block_pos++] = vala;
        block_write_data[block_pos++] = valb;
}
static inline void codegen_addbyte3(codeblock_t *block, uint8_t vala, uint8_t valb, uint8_t valc)
{
        if (block_pos > (BLOCK_MAX-3))
                fatal("codegen_addbyte3 over! %i\n", block_pos);
        block_write_data[block_pos++] = vala;
        block_write_data[block_pos++] = valb;
        block_write_data[block_pos++] = valc;
}
static inline void codegen_addbyte4(codeblock_t *block, uint8_t vala, uint8_t valb, uint8_t valc, uint8_t vald)
{
        if (block_pos > (BLOCK_MAX-4))
                fatal("codegen_addbyte4 over! %i\n", block_pos);
        block_write_data[block_pos++] = vala;
        block_write_data[block_pos++] = valb;
        block_write_data[block_pos++] = valc;
        block_write_data[block_pos++] = vald;
}

static inline void codegen_addword(codeblock_t *block, uint16_t val)
{
        if (block_pos > (BLOCK_MAX-2))
                fatal("codegen_addword over! %i\n", block_pos);
        *(uint16_t *)&block_write_data[block_pos] = val;
        block_pos += 2;
}

static inline void codegen_addlong(codeblock_t *block, uint32_t val)
{
        if (block_pos > (BLOCK_MAX-4))
                fatal("codegen_addlong over! %i\n", block_pos);
        *(uint32_t *)&block_write_data[block_pos] = val;
        block_pos += 4;
}

static inline void codegen_addquad(codeblock_t *block, uint64_t val)
{
        if (block_pos > (BLOCK_MAX-8))
                fatal("codegen_addquad over! %i\n", block_pos);
        *(uint64_t *)&block_write_data[block_pos] = val;
        block_pos += 8;
}

static void codegen_allocate_new_block(codeblock_t *block)
{
        /*Current block is full. Allocate a new block*/
        struct mem_block_t *new_block = codegen_allocator_allocate(block->head_mem_block, get_block_nr(block));
        uint8_t *new_ptr = codeblock_allocator_get_ptr(new_block);

        /*Add a jump instruction to the new block*/
        codegen_addbyte(block, 0xe9); /*JMP*/
        codegen_addlong(block, (uintptr_t)new_ptr - (uintptr_t)&block_write_data[block_pos + 4]);

        /*Set write address to start of new block*/
        block_pos = 0;
        block_write_data = new_ptr;
}

static inline void codegen_alloc_bytes(codeblock_t *block, int size)
{
        if (block_pos > ((BLOCK_MAX - size) - JMP_LEN_BYTES))
                codegen_allocate_new_block(block);
}

static inline int is_imm8(uint32_t imm_data)
{
        if (imm_data <= 0x7f || imm_data >= 0xffffff80)
                return 1;
        return 0;
}