Decimal Adjust Accumulator on the 4004

I'm currently writing a bit of code for the 4004 at the moment, and playing with it in the online Javascript emulator found here: http://e4004.szyc.org/emu/ According to http://e4004.szyc.org/iset.html (which I believe is copied straight from the MCS-4 Users Manual), the DAA instruction should increment the accumulator by 6 if carry is set or if the accumulator is greater than 9. Carry should be set following the instruction if the resulting addition generated a carry; otherwise it's unaffected. Let's say the accumulator is currently 9, carry is not set. I add another 9. Accumulator is now 2 with a carry. Running DAA should turn this into 8 with carry set, indicating that 9+9=(1)8. Am I thinking through this correctly? I ask, because according to the simulator's source code, DAA won't do that, if I'm following it correctly: function opDAA() { //DAA Decimal Adjust Accumulator if(A_reg > 9) A_reg += 6; C_flag=0; if (A_reg & 0xf0) {A_reg&=0xf; C_flag=1;} incPC(); } It says that it'll only add 6 if the accumulator is greater than 9, not if a carry is already set. It will then reset carry and set it if and only if there was a carry. Have I found a bug in the simulator? Am I misreading the MCS-4 Users Manual? In any event, this is my proposed fix to better match what the instruction description says: function opDAA() { //DAA Decimal Adjust Accumulator if((A_reg > 9) | (C_flag)) A_reg += 6; if (A_reg & 0xf0) {A_reg&=0xf; C_flag=1;} incPC(); } Seems to work as I would expect it to. Thanks, Kyle