(BOCA)

1. Embedded Computer Architecture 2 (BOCA) Bijzondere Onderwerpen Computer Architectuur Block E Irregular Dependency Graphs (1)

2. Irregular Dependency Graphs Consider the following DG, which represents the function: x y For convenience the nodes are from now on represented by squares. x + + + z

3. ALU 1 ALU 0 ALU 0 Towards shift-invariance 1 2 0 Making the wiring equal: 0 1 2 0 1 t = 0 ALU 0 1 ALU 0 t = 0 1 t = 1 1 0 t = 2 0 ALU t = 3 t = 1 2 z

4. muxn muxn ALU

5. v u0 u u1 u2 i0 i=2 i1 i2 u0 v u1

6. R A M R A M R A M R A M R A M R A M R A M R A M ALU ALU Transforming the DG to one with an ordinary RAM Recall our DG with control constants and replace the RAM a0 d0 1 read 0 0 a1 a0 d1 d0 1 1 0 read 0 a1 d1 1 a2 d2 ALU a2 d2 1 1 1 write a0 d0 0 1 read 0 a0 d0 0 a1 d1 0 a1 read d1 0 0 1 ALU d2 a2 a2 d2 2 2 1 write

7. ROM ROM ROM ROM ROM ROM 1 0 +1 +1 +1 +1 +1 +1 x 1 1 0 1 0 x 0 0 x 2 0 1 0 x 1 0 R A M ALU 1 R A M ALU 2 R A M ALU 3 R A M ALU 4 R A M ALU 5 R A M ALU

8. y0 y1 y2 y3 en c if( en && c==i ) yi = 1; else yi = 0;

9. cnt REG REG data memory R A M program memory ALU ROM program counter