Atmel ARM-Based Evaluation Kit for SAM4S16C, 32-Bit ARM® Cortex® Microcontroller ATSAM4S-WPIR-RD ATSAM4S-WPIR-RD Data Sheet
Product codes
ATSAM4S-WPIR-RD
SAM4S Series [DATASHEET]
Atmel-11100G-ATARM-SAM4S-Datasheet_27-May-14
144
12.6.6.1 MUL, MLA, and MLS
Multiply, Multiply with Accumulate, and Multiply with Subtract, using 32-bit operands, and producing a 32-bit result.
Syntax
Syntax
MUL{S}{cond} {Rd,} Rn, Rm ; Multiply
MLA{cond} Rd, Rn, Rm, Ra
; Multiply with accumulate
MLS{cond} Rd, Rn, Rm, Ra
; Multiply with subtract
where:
condis an optional condition code, see
condis an optional condition code, see
.
Sis an optional suffix. If S is specified, the condition code flags are updated on the result of the operation, see
.
Rdis the destination register. If Rd is omitted, the destination register is Rn.
Rn, Rmare registers holding the values to be multiplied.
Rais a register holding the value to be added or subtracted from.
Operation
The MUL instruction multiplies the values from Rn and Rm, and places the least significant 32 bits of the result in
Rd
Rn, Rmare registers holding the values to be multiplied.
Rais a register holding the value to be added or subtracted from.
Operation
The MUL instruction multiplies the values from Rn and Rm, and places the least significant 32 bits of the result in
Rd
.
The MLA instruction multiplies the values from Rn and Rm, adds the value from Ra, and places the least
significant 32 bits of the result in Rd.
The MLS instruction multiplies the values from Rn and Rm, subtracts the product from the value from Ra, and
The MLS instruction multiplies the values from Rn and Rm, subtracts the product from the value from Ra, and
places the least significant 32 bits of the result in Rd.
The results of these instructions do not depend on whether the operands are signed or unsigned.
Restrictions
In these instructions, do not use SP and do not use PC.
If the S suffix is used with the MUL instruction:
The results of these instructions do not depend on whether the operands are signed or unsigned.
Restrictions
In these instructions, do not use SP and do not use PC.
If the S suffix is used with the MUL instruction:
Rd
, Rn, and Rm must all be in the range R0 to R7
Rd
must be the same as Rm
The cond suffix must not be used.
Condition Flags
If S is specified, the MUL instruction:
If S is specified, the MUL instruction:
Updates the N and Z flags according to the result
Does not affect the C and V flags.
Examples
MUL
R10, R2, R5
; Multiply, R10 = R2 x R5
MLA
R10, R2, R1, R5 ; Multiply with accumulate, R10 = (R2 x R1) + R5
MULS
R0, R2, R2
; Multiply with flag update, R0 = R2 x R2
MULLT
R2, R3, R2
; Conditionally multiply, R2 = R3 x R2
MLS
R4, R5, R6, R7
; Multiply with subtract, R4 = R7 - (R5 x R6)
12.6.6.2 UMULL, UMAAL, UMLAL
Unsigned Long Multiply, with optional Accumulate, using 32-bit operands and producing a 64-bit result.
Syntax
Syntax
op{cond} RdLo, RdHi, Rn, Rm
where: