AN910 Datasheet, PDF (36/51 Pages) STMicroelectronics – ST7 AND ST9 PERFORMANCE BENCHMARKING

ST7 AND ST9 PERFORMANCE BENCHMARKING
7.3.9 ST7 MCU core
Programming model
Accumulator
- one 8-bit accumulator
- two 8-bit index registers
- other registers
16-bit program counter
16-bit stack pointer
condition code register
LD (X),A
ADD A,#A0
Instruction set
Cisc encoding
- CPI
2 cycles to 12 cycles
- average CPI
between 4 and 5 cycles
- IL
1 byte to 4 bytes
- average IL
between 2 and 3 bytes
- special addressing modes
indirect (short/long)
ST7 CPU
Cpu internal buses
16-bit address bus, 8-bit data bus
(to be confirmed)
Instruction processing
Standard
- sequential processing
Arithmetic Logic Unit
+x
8-bit datapath
- 8-bit operations
- special functions
8x8 unsigned multiplication
11 cycles
On-chip/Off-chip buses
- on-chip buses
16-bit address bus
8-bit data/program memory bus
Memory Space
Von Neumann organization
- linear data/program memory space
64 kbytes
256-byte zero page
128-byte peripheral register space
direct addressable
upper 32-byte interrupt vector table = 14 interrupts
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