Texas Instruments C28 Series, Student Manual

Page: 292 / 342

Indirect Addressing
Indirect Addressing
Indirect Addressing
Indirect Addressing
–
–
“
“
*
*
”
”
Auxiliary Registers (
Auxiliary Registers (
XARn
XARn
) used to access full
) used to access full
data memory space
data memory space
Address Register Arithmetic Unit (ARAU) used
Address Register Arithmetic Unit (ARAU) used
to modify the to modify the XARn XARn
Access data from arrays anywhere in data
Access data from arrays anywhere in data
memory in an orderly fashion memory in an orderly fashion
Data Memory
Data Memory
XAR0
XAR0
XAR1 XAR1
XAR2
XAR2
XAR3 XAR3
XAR4 XAR4
XAR5 XAR5
XAR6 XAR6
XAR7 XAR7
ARAU
ARAU
Any of eight hardware pointers (ARs) may be employed to access values from the first 64K of
data memory. Auto-increment or decrement is supported at no additional cycle cost. XAR register
formats offer larger 32-bit widths, allowing them to access across the full 4-Giga words data
space.
Indirect Addressing Modes
Indirect Addressing Modes
Auto Auto - - increment / decrement: * increment / decrement: * XARn XARn ++, * ++, * -- -- XARn XARn
Post Post - - increment or Pre increment or Pre - - decrement decrement
Offset: *+
Offset: *+
XARn
XARn
[AR0 or AR1], *+
[AR0 or AR1], *+
XARn
XARn
[3bit]
[3bit]
Offset by 16
Offset by 16
-
-
bit AR0 or AR1, or 3
bit AR0 or AR1, or 3
-
-
bit constant
bit constant
Stack Relative: *
Stack Relative: *
-
-
SP[6bit]
SP[6bit]
Index by 6
Index by 6
-
-
bit offset (optimal for C)
bit offset (optimal for C)
Immediate Direct: *(0:16bit)
Immediate Direct: *(0:16bit)
Access low 64K
Access low 64K
Circular: *AR6%++
Circular: *AR6%++
AR1(7:0) is buffer size
AR1(7:0) is buffer size
XAR6 is current address
XAR6 is current address
B - 10 C28x - Appendix B - Addressing Modes