
ADDRESS SPACES
S3C8248/C8245/P8245/C8247/C8249/P8249
2-10
16-Byte
Contiguous
working
Register block
Register File
Contains 32
8-Byte Slices
0 0 0 0 0 X X X
RP1
1 1 1 1 0 X X X
RP0
0H (R0)
7H (R15)
F0H (R0)
F7H (R7)
8-Byte Slice
8-Byte Slice
Figure 2-7. Non-Contiguous 16-Byte Working Register Block
+
+
PROGRAMMING TIP — Using the RPs to Calculate the Sum of a Series of Registers
Calculate the sum of registers 80H–85H using the register pointer. The register addresses from 80H through 85H
contain the values 10H, 11H, 12H, 13H, 14H, and 15 H, respectively:
SRP0
#80H
; RP0
←
80H
ADD
R0,R1
; R0
←
R0 + R1
ADC
R0,R2
; R0
←
R0 + R2 + C
ADC
R0,R3
; R0
←
R0 + R3 + C
ADC
R0,R4
; R0
←
R0 + R4 + C
ADC
R0,R5
; R0
←
R0 + R5 + C
The sum of these six registers, 6FH, is located in the register R0 (80H). The instruction string used in this
example takes 12 bytes of instruction code and its execution time is 36 cycles. If the register pointer is not used
to calculate the sum of these registers, the following instruction sequence would have to be used:
ADD
80H,81H
; 80H
←
(80H) + (81H)
ADC
80H,82H
; 80H
←
(80H) + (82H) + C
ADC
80H,83H
; 80H
←
(80H) + (83H) + C
ADC
80H,84H
; 80H
←
(80H) + (84H) + C
ADC
80H,85H
; 80H
←
(80H) + (85H) + C
Now, the sum of the six registers is also located in register 80H. However, this instruction string takes 15 bytes of
instruction code rather than 12 bytes, and its execution time is 50 cycles rather than 36 cycles.
Содержание C8245
Страница 31: ...ADDRESS SPACES S3C8248 C8245 P8245 C8247 C8249 P8249 2 20 NOTES ...
Страница 107: ...INTERRUPT STRUCTURE S3C8248 C8245 P8245 C8247 C8249 P8249 5 18 NOTES ...
Страница 195: ...INSTRUCTION SET S3C8248 C8245 P8245 C8247 C8249 P8249 6 88 NOTES ...
Страница 221: ...I O PORTS S3C8248 C8245 P8245 C8247 C8249 P8249 9 16 NOTES ...
Страница 245: ...16 BIT TIMER 0 1 S3C8248 C8245 P8245 C8247 C8249 P8249 12 10 NOTES ...
Страница 249: ...WATCH TIMER S3C8248 C8245 P8245 C8247 C8249 P8249 13 4 NOTES ...
Страница 267: ...A D CONVERTER S3C8248 C8245 P8245 C8247 C8249 P8249 15 6 NOTES ...
Страница 299: ...S3P8245 P8249 OTP S3C8248 C8245 P8245 C8247 C8249 P8249 21 8 NOTES ...
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Страница 315: ...BOOK SPINE TEXT SAMSUNG Logo S3C8248 C8245 P8245 C8247 C8249 P8249 Microcontrollers User s Manual Rev 3 March 2002 ...