668-0003-C Rabbit Semiconductor, 668-0003-C Datasheet - Page 38

• Manufacturer Part Number: 668-0003-C
• Description: IC CPU RABBIT2000 30MHZ 100PQFP
• Manufacturer: Rabbit Semiconductor

Specifications of 668-0003-C

• Rohs Status: RoHS non-compliant
• Processor Type: Rabbit 2000 8-Bit
• Speed: 30MHz
• Voltage: 2.7V, 3V, 3.3V, 5V
• Mounting Type: Surface Mount
• Package / Case: 100-MQFP, 100-PQFP
• Features: -
• Other names: 316-1004; 668-0003

3.4.4 Comparisons of Integers
Unsigned integers may be compared by testing the zero and carry flags after a subtract
operation. The zero flag is set if the numbers are equal. With the SBC instruction the carry
cleared is set if the number subtracted is less than or equal to the number it is subtracted
from. 8-bit unsigned integers span the range 0–255. 16-bit unsigned integers span the
range 0–65535.
If A is in HL and B is in DE these operations can be performed as follows assuming that
the object is to set HL to 1 or 0 depending on whether the compare is true or false.
32
OR a
SBC HL,DE
A>=B
A<B
A==B
A>B
A<=B
; compute HL<DE
; unsigned integers
; EX DE,HL
OR a
SBC HL,DE
SBC HL,HL
BOOL HL
;unsigned integers
; compute HL>=DE or DE>=HL - check for !C
; EX DE,HL
OR a
SBC HL,DE
SBC HL,HL
INC HL
; 0 if C , 1 if !C
;
: compute HL==DE
OR a
SBC HL,DE
BOOL HL
DEC HL
BOOL HL
;
!C
C
Z
!C & !Z
C v Z
; clear carry
; zero is equal
; force to zero, 1
; invert logic
; 12 clocks total -logical not, 1 for inputs equal
; uncomment for DE<HL
; clear carry
; C set if HL<DE
; HL-HL-C --
; set to 1 if carry, else zero
; else result == 0
; uncomment for DE<=HL
; clear carry
; !C if HL>=DE
; HL-HL-C - zero if no carry, -1 if C
; 14 / 16 clocks total -if C after first SBC result 1,
; else 0
; clear carry
; HL=A and DE=B
-1 if carry set
Rabbit 2000 Microprocessor User’s Manual