Computer Architecture Lab/WS2007/Project -1 Lab4/AssemblerSyntax

Assembler syntax

Arithmetic functions

ADD("1","0","1E"); /* Add Random Number (contained in reserved Register $1E) with 0 (contained always in reserved Register $0) and store the result in $1 */
ADDU("1","3","2"); /* Adds unsigned values contained in $3 with unsigned value in $2 and stores the result in $1 */
SUB("3","1","2"); /* Substract $1 by $2 and store the result in $3 */
SUBU("1","3","2"); /* Substracts unsigned values contained in $3 with unsigned value in $2 and stores the result in $1 */

Logical functions:

AND("1","3","2"); /* $1 = $3 and $2 */
OR("1","3","2");  /* $1 = $3 or $2 */
XOR("1","3","2"); /* $1 = $3 xor $2 */

Shift functions:

SLL("2","5","1");  /* Shift the value contained in $5 left by 1 and store the result in $2 */
SLLV("2","5","1"); /* Shift the value contained in $5 left by value of $1 and store the result in $2 */
SRA("1","4","3");  /* Shift the value contained in $4 arithmetical right by 3 and store the result in $1 */
SRL("A","3","1");  /* Shift the value contained in $3 right by value of $1 and store the result in $A */
SRLV("A","5","1"); /* Shift the value contained in $5 left by 1 and store the result in $A */

(Un)Conditional functions:

BZS(LABEL); /* Branch if ZeroFlag is set, jump to LABEL */
BZC(LABEL); /* Branch if ZeroFlag is clear, jump to LABEL */
BNS(LABEL); /* Branch if NegativeFlag is set, jump to LABEL */
BNC(LABEL); /* Branch if NegativeFlag is clear, jump to LABEL */
BOS(LABEL); /* Branch if OverflowFlag is set, jump to LABEL */
BOC(LABEL); /* Branch if OverflowFlag is clear, jump to LABEL */
BOR(LABEL); /* Branch if RandomFlag is set, jump to LABEL */
BR(LABEL);  /* jump to LABEL */
JR("3"); /* Jump to address contained in Register $3 */

Load and Store functions:

LLI("2","1"); /* Load value 1 to Register $2 */
LW("3","2"); /* Load value contained in Register $2 to Register $3 */
SW("3","2"); /* Store value contained in Register $2 to Register $3 */

NOOP:

NOOP(); /* do nothing */

RAMENTER: Writes a String into the RAM

RAMENTER ("4","7","11","Hello World. ",&pc);
/*
"$1 ... Addressregister, $2 ... Length register, $3 ... Increment Register
Arguments: 
$1 ... Destination Address Register Number
$2 ... Buffer Length Register: Gets the number of stored characters
$3 ... Address Step Register: defines the address distance between two stored characters in RAM
$4 ... String
&pc .. (decoration)
*/

CALL Function

CALL (Label) /* Jump to Function "Label" */

RETURN from CALL

RETURN

Simple UART output

UART_SEND_STRING("Hello World",&pc); /* writes "Hello World" to the Terminal */

Debug output

DEBUG_SEND("1",&pc); /* Writes "Content of reg 0x01 is: " and the hex-value of the value contained in $1 */

Load a 32-bit Value:

LOAD_BIG_NUMBER("1","11","12345678",&pc); /* Load the whole 32-Bit hex-value into $1 with the temporary help of $11 */

Code Samples

Substraction example:

LLI("1",6);       /* Load to Value 6 to Register $1 */
LLI("2",5);       /* Load to Value 5 to Register $2 */
SUB("3","1","2"); /* Substract $1 by $2 and store the result in $3 */

Add 2 numbers and check if there is an overflow:

LABEL(START)        /* Define Label START */
ADD("1","3","4");   /* ADD $3 with $4 and store the result in $1 */
BOS(OVERFLOWLABEL); /* if OverflowFlag is set jump to OVERFLOWLABEL */
BR(START);          /* jump to START */
LABEL(OVERFLOWLABEL)/* define Label OVERFLOWLABEL */
UART_SEND_STRING("Warning: Overflow after ADD Operation!",&pc); /* Send warning to UART */

for further program samples go to Code Samples