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What is MOVEQ in assembly?
According to the NXP Programmers Reference Manual (reference below), the command MOVEQ (MOVE QUICK) is described as: Moves a byte of immediate data to a 32-bit data register. The data in an 8-bit field within the operation word is sign- extended to a long operand in the data register as it is transferred.
What size in bits are the addresses sent from the 68000 processor to main memory when performing a load read or store write operation circle one of the options below?
32 bits
It is 32 bits wide, because memory addresses in the 68000 system are 32-bit numbers.
What does MOVQ do in assembly?
The movq instruction moves the 1st argument (passed in %rdi) to its place on the stack. The argument occupies the first stack position (stack entries are 8 bytes) after the base pointer (%rbp). 0(%rbp) stores the previous frame’s base pointer.
What does ADDQ do in assembly?
1 Answer. The addq a,b instruction adds the contents of a to b . So if rcx = 0x1 , rax = 0x100 and we have 0xff at address 0x100 , then add %rcx,(%rax) adds 0x1 in rcx to 0xff at address 0x100 , yielding 0x100 at address 0x100 as the worksheet correctly indicates.
How many bits are required to hold a memory address?
The processor uses 32 bits to store an address. With 32 bits, you can store 2^32 distinct numbers, ranging from 0 to 2^32 – 1. “Byte addressing” means that each byte in memory is individually addressable, i.e. there is an address x which points to that specific byte.
What does RBP mean in assembly?
base pointer
rbp is the base pointer, which points to the base of the current stack frame, and rsp is the stack pointer, which points to the top of the current stack frame.
What is EAX in assembly?
eax is the 32-bit, “int” size register. It was added in 1985 during the transition to 32-bit processors with the 80386 CPU. It was added in 1979 with the 8086 CPU, but is used in DOS or BIOS code to this day. al and ah are the 8-bit, “char” size registers.
What’s the difference between move 0 and move 0 in 68000?
Most assemblers quietly assemble MOVE #0,An as a MOVEA (move to an address register) instruction without nagging the programmer about the distinction between MOVE and MOVEA. But the 68000 treats data and address values very differently.
How are two operand instructions reversed on the 68000?
The syntax of two-operand instructions may be reversed from other machines you’re used to. For instance, the 68000 instruction MOVE.W D0,D1 is equivalent to LOAD D1,D0 on some other machines; that is, the contents of the D0 register are moved into D1. On the 68000, the destination register — the one affected by the instruction — is always second.
How to learn 68000 assembly programming by example?
Beginners Series – lets learn the basic 68000 commands by example! Lesson 4 – Stack, Traps, and Maths! Lesson 5 – Bits and swaps! Lesson 6 – More Bits… Extends and Macros Hello World Series – Lets look at simple Hello World examples – each with a single ASM file. Lesson P19 – Sound on the NeoGeo via FM with the YM2610 (and Genesis!)
How many registers are there in the 68000?
The 68000 has a far more advanced register set than the 8 bit machines we are used to…it has 8 Data registers for general use (like BC) , 8 Address registers for memory functions and even stack pointers! (Can be used as HL,DE and even SP!)…