Memory Flashcards
how to change a value in memory
store in a register, change that, store back into memory
how do we terminate a string in memory
null terminate eg 0x00
psuedo code for loading a bytesized character from memory
ch = byte [address]
psuedo code for storing a byte into register
byte [address] = ch
ldrb means
load with byte
strb means
store byte
ldrh means
Load half word
ldr means
load word
strh measn
store hafl word
str means
store word
which has a reversed operand order str or ldr
STR
what does rom stand for
read only memory
what does ram stand for
random access memory
can rom be modified by a running program
no
can ram be modified by a running program
yes
how to add one to address in memory and also load the byte from memory into a register (R1)
memory in r4
LDRB R1, [R4], #1
what happens when we load a byte sized value from memory into a word sized register
byte value in stored in least significant bit,
3 remaining bytes are set to 0
what is little endian byte storing
when the least significant byte of the word/halfword is stored at the lower address in memory
what is big endian byte stroing
when the most significant bit of the word/halfword is stored in the lower address of memory
default on vs code little endian or big endian
little endian
how to use ldr with signed numbers
ldrs
what will the remaining digits in the word be padded with if negative
1s
