package sim_8086

import "core:os"
import "core:fmt"
import "core:math"
import "core:strings"

execute_instruction :: proc(inst: Instruction) {
    #partial switch inst.opname {
        case .MOV:
        if reg_id,ok := inst.dst.(RegisterId); ok {
            // val := registers[reg_id.id].value.full
            #partial switch val in inst.src {
            case Immediate8:
                if reg_id.access == .Low {
                    registers[reg_id.id].value.low  = (u8)(val)
                } else {
                    registers[reg_id.id].value.high  = (u8)(val)
                }
            case ImmediateU8:
                if reg_id.access == .Low {
                    registers[reg_id.id].value.low  = (u8)(val)
                } else {
                    registers[reg_id.id].value.high  = (u8)(val)
                }
            case Immediate16:
                registers[reg_id.id].value.full = (u16)(val)
            case RegisterId:
                switch val.access {
                case .Low, .High:
                    value := val.access == .Low ? registers[val.id].value.low : registers[val.id].value.high
                    if reg_id.access == .Low {
                        registers[reg_id.id].value.low = value
                    } else {
                        registers[reg_id.id].value.high = value
                    }
                case .Full:
                    registers[reg_id.id].value.full = registers[val.id].value.full
                }
            case SegmentRegister:
                registers[reg_id.id].value.full = segment_registers[val].value.full
            }
            // fmt.printfln("%s:%04x->%04x", registers[reg_id].fullname, val, registers[reg_id].value.full)
        } else if reg_id,ok := inst.dst.(SegmentRegister); ok {
            // val := segment_registers[reg_id].value.full
            #partial switch val in inst.src {
            case Immediate8:
                segment_registers[reg_id].value.low = (u8)(val)
            case ImmediateU8:
                segment_registers[reg_id].value.low = (u8)(val)
            case Immediate16:
                segment_registers[reg_id].value.full = (u16)(val)
            case RegisterId:
                segment_registers[reg_id].value.full = registers[val.id].value.full
            }
            // fmt.printfln("%s:%04x->%04x", segment_registers[reg_id].fullname, val, segment_registers[reg_id].value.full)
        }
    }
}