dsp56800e Freescale Semiconductor, Inc, dsp56800e Datasheet - Page 213

• Manufacturer Part Number: dsp56800e
• Description: 16-bit Digital Signal Controller Core
• Manufacturer: Freescale Semiconductor, Inc

Section 6.8.5.3, “Modulo Addressing for AGU Arithmetic Instructions,” lists the AGU arithmetic
instructions that can be affected by modulo arithmetic.
Freescale Semiconductor
DECA Rn
DECA.L Rn
LSRA Rn
NEGA Rn
SUBA Rm,Rn
SUBA #xx,SP
SXTA.B Rn
SXTA.W Rn
TFRA Rm,Rn
TSTA.B Rn
TSTA.W Rn
TSTA.L Rn
TSTDECA.W Rn
ZXTA.B Rn
ZXTA.W Rn
Instruction
Table 6-5. AGU Address Arithmetic Instructions (Continued)
Rn = Rn–1
Rn = Rn–2
Rn = (Rn>>1)
Rn = –(Rn)
Rn = Rn–Rm
SP = SP–#xx
Rn = sign_extend(Rn,7)
Rn = sign_extend(Rn,15)
Rn = Rm
(Rn & 0x0000FF)–0
(Rn & 0x00FFFF)–0
Rn–0
Rn = Rn–1
Rn = Rn & 0x0000FF
Rn = Rn & 0x00FFFF
Address Calculation
Address Generation Unit
Decrement by one.
Decrement by two.
Logical right shift.
Negate register value
#x is a 6-bit unsigned value.
Sign extend the upper 16 bits of a register using
the value of bit 7 for sign extension.
Sign extend the upper 8 bits of a register using
the value of bit 15 for sign extension.
Transfer one 24-bit register to another.
Test byte—the result is not stored anywhere, but
the condition codes are set based on the lower 8
bits of the result.
Test word—the result is not stored, but the con-
dition codes are set based on the lower 16 bits
of the result.
Test long—the result is not stored, but the condi-
tion codes are set based on the result.
Test the lower 16 bits of the value in the Rn reg-
ister, set the condition codes, and then decre-
ment the register.
Zero extend a byte value.
Zero extend a word value.
AGU Arithmetic Instructions
Comments
6-19