ADDRESS SPACES
KS57C2308/P2308/C2316/P2316
2-10
Special-Purpose Working Registers
Register A is used as a 4-bit accumulator and double register EA as an 8-bit accumulator. The carry flag can also
be used as a 1-bit accumulator.
8-bit double registers WX, WL and HL are used as data pointers for indirect addressing. When the HL register
serves as a data pointer, the instructions LDI, LDD, XCHI, and XCHD can make very efficient use of working
registers as program loop counters by letting you transfer a value to the L register and increment or decrement it
using a single instruction.
C
A
EA
1-BIT
ACCUMULATOR
4-BIT
ACCUMULATOR
8-BIT
ACCUMULATOR
Figure 2-6. 1-Bit, 4-Bit, and 8-Bit Accumulator
Recommendation for Multiple Interrupt Processing
If more than four interrupts are being processed at one time, you can avoid possible loss of working register data
by using the PUSH RR instruction to save register contents to the stack before the service routines are executed
in the same register bank. When the routines have executed successfully, you can restore the register contents
from the stack to working memory using the POP instruction.
Summary of Contents for KS57C2308
Page 30: ...ADDRESS SPACES KS57C2308 P2308 C2316 P2316 2 22 NOTES ...
Page 168: ...SAM47 INSTRUCTION SET KS57C2308 P2308 C2316 P2316 5 94 NOTES ...
Page 170: ......
Page 206: ...POWER DOWN KS57C2308 P2308 C2316 P2316 8 8 NOTES ...
Page 210: ...RESET KS57C2308 P2308 C2316 P2316 9 4 NOTES ...
Page 222: ...I O PORTS KS57C2308 P2308 C2316 P2316 10 12 NOTES ...
Page 272: ...LCD CONTROLLER DRIVER KS57C2308 P2308 C2316 P2316 12 24 NOTES ...
Page 280: ...SERIAL I O INTERFACE KS57C2308 P2308 C2316 P2316 13 8 NOTES ...
Page 294: ...MECHANICAL DATA KS57C2308 P2308 C2316 P2316 15 2 NOTES ...
Page 310: ...KS57P2308 P2316 OTP KS57C2308 P2308 C2316 P2316 16 16 NOTES ...
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