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Adds single-byte memory interface to the VM.

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This commit is contained in:
Felix Queißner 2016-05-21 19:26:08 +02:00
parent c404e99e59
commit 5072f2c51e
2 changed files with 55 additions and 0 deletions
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42
prototypes/supervm/vm.c
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@ -7,6 +7,20 @@ static void cmd_copy(CommandInfo *info)
info->output = info->input0;
}
// | 1 | STORE | output = MEMORY[input0] = input1 |
// | 2 | LOAD | output = MEMORY[input0] |
static void cmd_load(Process *p, CommandInfo *info)
{
info->output = vm_read_byte(p, info->input0);
}
static void cmd_store(Process *p, CommandInfo *info)
{
vm_write_byte(p, info->input0, info->input1);
info->output = info->input1;
}
static void cmd_math(CommandInfo *info)
{
switch(info->additional)
@ -97,6 +111,8 @@ int vm_step_process(Process *process)
switch(instr.command)
{
case VM_CMD_COPY: cmd_copy(&info); break;
case VM_CMD_STORE: cmd_store(process, &info); break;
case VM_CMD_LOAD: cmd_load(process, &info); break;
case VM_CMD_MATH: cmd_math(&info); break;
case VM_CMD_SYSCALL: vm_syscall(process, &info); break;
case VM_CMD_HWIO: vm_hwio(process, &info); break;
@ -154,3 +170,29 @@ uint32_t vm_peek(Process *process)
vm_assert(process != NULL, "process must not be NULL.");
return process->stack[process->stackPointer];
}
uint8_t vm_read_byte(Process *process, uint32_t address)
{
vm_assert(process != NULL, "process must not be NULL.");
uint32_t page = address / process->mmap.pageSize;
uint32_t index = address % process->mmap.pageSize;
vm_assert(page < process->mmap.length, "Out of memory.");
return process->mmap.pages[page][index];
}
void vm_write_byte(Process *process, uint32_t address, uint8_t value)
{
vm_assert(process != NULL, "process must not be NULL.");
uint32_t page = address / process->mmap.pageSize;
uint32_t index = address % process->mmap.pageSize;
vm_assert(page < process->mmap.length, "Out of memory.");
process->mmap.pages[page][index] = value;
}

13
prototypes/supervm/vm.h
View file

@ -140,6 +140,19 @@ uint32_t vm_pop(Process *process);
*/
uint32_t vm_peek(Process *process);
/**
* Reads a byte from process memory.
* @arg process
* @arg address The address to read from.
*/
uint8_t vm_read_byte(Process *process, uint32_t address);
/**
* Writes a byte to process memory.
* @arg process
* @arg address The address to read from.
*/
void vm_write_byte(Process *process, uint32_t address, uint8_t value);
// The following functions need to be host-implemented.