Examples of programs

The parallelepiped surface

Let's calculate full surface of the parallelepiped with ribs A, B and C, using "E97". A, B and C values is taken from memory cells.

The parallelepiped surface formula is the following:
S = 2 * (A * B + A * C + B * C) = 2 * [A * (B + C) + B * C]
Let's program it in "E97" codes:

Latin letter input

The program gets latin letter and makes it upper-case. The upper- and lower-case characters differ in one bit only. For example, ASCII codes for letter R, are the following:
R - 0101 0010; r - 0111 0010.
To reset the 5-th bit, logical operation AND with constant 1101 1111 = DF can be used: if constant bit is zero, the result bit will be zero too, otherwise it repeats the congruent character's bit.

Address	Code	Operation	Comments
0000	0E6D	30 ==> SP	set SP for correct
0002	0030		subroutine calls
0004	9C0D	call subroutine	symbol input
0006	40FE	40FE	(without echo!)
0008	0101	R0 ==> R1	save input character
000A	07D0	DF and R0 ==> R0	make upper-case character
000C	00DF
000E	9C0D	call subroutine	result's output
0010	4088	4088
0012	0F00	halt

Find maximum

Arbitrary integer numbers are stored in registers R1, R2 and R3. Find maximum of them.

At first we'll copy maximum of R1 and R2 to R0. Then, if R3>R0, it's necessary to replace R0 value by R3.

Address	Code	Operation	Comments
0000	0412	compare R2 and R1
0002	3D04	if <0, then pc=pc+4	to 0008
0004	0120	R2 ==> R0	remember R2
0006	1D02	pc=pc+2	to 000A - bypass second branch
0008	0110	R1 ==> R0	remember R1
000A	0403	compare R3 with R0
000C	3D02	if <0, then pc=pc+2	to 0010
000E	0130	R3 ==> R0	remember R3
0010	0F00	halt