these terms are assembler directives. you can get a very detailed explanation for each one looking at the manual from the assembler that you are using.

an an example for EQU:

time1 equ 0ah;

that line tells the assembler that the word time1 can be used as a name for the value 0ah, so when you are coding you can use the name time1 instead of 0ah.

when you have lots of variables in your code you can see this as very useful

for your question, check each bit from P1 and look a 1 to 0 transition (P1.0 was 1 last time checked, now P1.0 is 0, do something)

hth

orlando