note each undeclared identifier is reported only once for each function it appears in #define GET_GPIO_VALUELSDA_GPIO_PIN readlGPIO_MODE_BASE + LSDA_GPIO_PIN 16 4 & 1 LSDA_GPIO_PIN 16 2;

This is a macro that takes a parameter LSDA_GPIO_PIN and returns the value of the GPIO pin specified by that parameter. It does this by performing a bitwise AND operation between the value read from a specific memory address (determined by the value of LSDA_GPIO_PIN) and a bit mask that is shifted by a certain amount.

However, this macro relies on the existence of certain variables or constants that are not defined within the macro itself, such as GPIO_MODE_BASE. If these variables are not declared or defined before the macro is used, the compiler will generate an "undeclared identifier" error