Reads the status of keyboard and joysticks and stores it in the 10 bytes reserved as cpct_keyboardStatusBuffer. (Interrupt-Unsafe version)
void cpct_scanKeyboard ()
cpct_keyboardStatusBuffer filled up with pressed / not pressed info about all the 80 available Amstrad CPC’s keys / buttons.
call cpct_scanKeyboard_i_asm
This function reads the pressed / not pressed status of the entire set of 80 keys / buttons from the Amstrad CPC and writes this status in cpct_keyboardStatusBuffer. cpct_keyboardStatusBuffer is a 10-bytes buffer (80 bits) that holds 1 bit for each key / button of the Amstrad CPC, meaning 0 = pressed, and 1 = not pressed. This codification is the same as the one returned by the AY-3-8912 chip, which reads the keyboard when Programmable Peripheral Interface (PPI) chip demands it. For more details on how all this process works, check Keyboard topic.
The function does not disable nor reenable interrupts (contrary to what cpct_scanKeyboard does). This means that this function is Interrupt-Unsafe. If an interrupt happens during the execution of this function’s code, the output may be corrupt. To prevent this from happening, you should ensure that this function is called only in interrupt-safe places. You may call in a syncronized part of your code, knowing that no interrupt will happen there, inside a manually disabled interrupts section, or inside an interrupt service routine. In any case, is up to you to ensure that no interrupt happens during key scanning.
AF, BC, DE, HL
47 bytes
Case | microSecs (us) | CPU Cycles ------------------------------------ Any | 210 | 840 ------------------------------------
This fragment of code is based on a scanKeyboard code issued by CPCWiki. http://www.cpcwiki.eu
10-bytes (80-bits) array containing pressed / not pressed status of all the keys / buttons the Amstrad CPC can manage (up to 80).
extern u8 cpct_keyboardStatusBuffer[10]