Ripple Carry Adder

This is a generic, parameterized (sort of), implementation of a Ripple Carry Adder (RCA) in Verilog. It's been verified to work up to 64 bits, but nothing beyond that.

Generic Synth

Command used: yosys -p 'synth -top rca' rca.v

Equation: 0x² + 5x + 0
R²: 1

XLEN	ANDNOT	NAND	ORNOT	XNOR	Total Cells
1	1	1	1	2	5
2	2	2	2	4	10
4	4	4	4	8	20
8	8	8	8	16	40
16	16	16	16	32	80
32	32	32	32	64	160
64	64	64	64	128	320
128	128	128	128	256	640

ECP5

Command used: yosys -p 'synth_ecp5 -top rca' rca.v

Equation¹: (2.68E-03)x² + 6.72x - 0.04
R²: 0.999

XLEN	PFUMX	LUT4	L6MUX21	Total Cells
1	0	2	0	2
2	2	5	0	7
4	4	10	0	14
8	13	32	6	51
16	23	68	15	106
32	45	135	30	210
64	91	286	63	440
128	180	591	126	897

Not entirely accurate, huge margin for error ↩

XLEN	ANDNOT	NAND	ORNOT	XNOR	Total Cells
1	1	1	1	2	5
2	2	2	2	4	10
4	4	4	4	8	20
8	8	8	8	16	40
16	16	16	16	32	80
32	32	32	32	64	160
64	64	64	64	128	320
128	128	128	128	256	640

XLEN	PFUMX	LUT4	L6MUX21	Total Cells
1	0	2	0	2
2	2	5	0	7
4	4	10	0	14
8	13	32	6	51
16	23	68	15	106
32	45	135	30	210
64	91	286	63	440
128	180	591	126	897

XLEN	ANDNOT	NAND	ORNOT	XNOR	Total Cells
1	1	1	1	2	5
2	2	2	2	4	10
4	4	4	4	8	20
8	8	8	8	16	40
16	16	16	16	32	80
32	32	32	32	64	160
64	64	64	64	128	320
128	128	128	128	256	640

XLEN	PFUMX	LUT4	L6MUX21	Total Cells
1	0	2	0	2
2	2	5	0	7
4	4	10	0	14
8	13	32	6	51
16	23	68	15	106
32	45	135	30	210
64	91	286	63	440
128	180	591	126	897

Hammersamatom/rca

Ripple Carry Adder

Generic Synth

ECP5

Footnotes

XLEN	ANDNOT	NAND	ORNOT	XNOR	Total Cells
1	1	1	1	2	5
2	2	2	2	4	10
4	4	4	4	8	20
8	8	8	8	16	40
16	16	16	16	32	80
32	32	32	32	64	160
64	64	64	64	128	320
128	128	128	128	256	640

XLEN	PFUMX	LUT4	L6MUX21	Total Cells
1	0	2	0	2
2	2	5	0	7
4	4	10	0	14
8	13	32	6	51
16	23	68	15	106
32	45	135	30	210
64	91	286	63	440
128	180	591	126	897