ProgCom.CPUem.extndInst C# (CSharp) Method

        private int extndInst(int address, int regA, int regB, int regC, int valA, int valB, int valC, bool immed)
        {
            int inst = address >> 8;
            if (immed) {
                valC = valC & 255;
            }
            int extraExecTime = 0;
            int tmp;
            switch (inst) {
                case 0://true nop
                    break;
                //8-11 partial moves
                case 8://movb
                    valA ^= (valA & (255 << (8 * (valC & 3))));
                    register[regA] = valA | (valB & (255 << (8 * (valC & 3))));
                    break;
                case 9://movhw
                    valA ^= (valA & (65535 << (16 * (valC & 1))));
                    register[regA] = valA | (valB & (65535 << (16 * (valC & 1))));
                    break;
                case 10://movbl
                    valA ^= (valA & (255 << (8 * (valC & 3))));
                    register[regA] = valA | ((valB & 255) << (8 * (valC & 3)));
                    break;
                case 11://movhwl
                    valA ^= (valA & (65535 << (16 * (valC & 1))));
                    register[regA] = valA | ((valB & 65535) << (16 * (valC & 1)));
                    break;
                //12-15, might extend partial moves here
                //16-24, comparison instructions
                case 16://le
                    if(valB < valC) {
                        register[regA] = 1;
                    } else {
                        register[regA] = 0;
                    }
                    break;
                case 17://leq
                    if(valB <= valC) {
                        register[regA] = 1;
                    } else {
                        register[regA] = 0;
                    }
                    break;
                case 18://eq
                    if(valB == valC) {
                        register[regA] = 1;
                    } else {
                        register[regA] = 0;
                    }
                    break;
                case 19://neq
                    if(valB != valC) {
                        register[regA] = 1;
                    } else {
                        register[regA] = 0;
                    }
                    break;
                case 20://leu
                    if ((UInt32)valB < (UInt32)valC) {
                        register[regA] = 1;
                    } else {
                        register[regA] = 0;
                    }
                    break;
                case 21://lequ
                    if ((UInt32)valB <= (UInt32)valC) {
                        register[regA] = 1;
                    } else {
                        register[regA] = 0;
                    }
                    break;
                //22-24, reserved
                //24-27, logical arithmetic
                case 24://land
                    if (valB != 0 && valC != 0) {
                        register[regA] = 1;
                    } else {
                        register[regA] = 0;
                    }
                    break;
                case 25://lor
                    if (valB != 0 || valC != 0) {
                        register[regA] = 1;
                    } else {
                        register[regA] = 0;
                    }
                    break;
                case 26://lxor
                    if ((valB != 0 && valC == 0) || (valB == 0 && valC != 0)) {
                        register[regA] = 1;
                    } else {
                        register[regA] = 0;
                    }
                    break;
                //27, reserved
                //28-31, bit searching
                case 28://msb
                    tmp = 31;
                    while (((valC >> tmp) & 1) == 0 && tmp > 0) {
                        tmp--;
                    }
                    register[regA] = 1 << tmp;
                    break;
                case 29://lsb
                    tmp = valC - 1;
                    tmp = tmp ^ valC;
                    register[regA] = tmp;
                    break;
                case 30://msbn
                    tmp = 31;
                    while (((valC >> tmp) & 1) == 0 && tmp > 0) {
                        tmp--;
                    }
                    register[regA] = tmp;
                    break;
                case 31://lsbn
                    tmp = 0;
                    while (((valC >> tmp) & 1) == 0 && tmp < 31) {
                        tmp++;
                    }
                    register[regA] = tmp;
                    break;
                //32-35, bit twiddling
                case 32://sbit, set bit
                    register[regA] = valB | (1 << (valC & 0x1f));
                    break;
                case 33://sbitc, set bit conditional
                    register[regA] = valB != 0 ? valA | (1 << (valC & 0x1f)) : valA;
                    break;
                case 34://gbit, get bit
                    register[regA] = (Int32)((UInt32)(valB & (1 << (valC & 0x1f)))) >> (valC &0x1f);
                    break;
                case 35://xbit, xor bit
                    register[regA] = valB ^ (1 << (valC & 0x1f));
                    break;
                default:
                    spawnException(258);
                    return 0;
            }
            return extraExecTime;
        }