Program 22: Word copy and checksum

Program catalogue · Instruction reference · Executable reference

Purpose

Provide a mixed-memory workload that copies eight words while accumulating their checksum.

This is one of the six workload fixtures. This page specifies its instructions and architectural result; pipeline cycles, stalls, and throughput are implementation-specific and are not established by this reference run.

Setup

Property	Value
Benchmark workload ID	program-22
Headless selection	--program 22
Visualizer scenario	rv32i-program22
Registered test	RV32ISingleCycleSystemTest/program-22
Instruction image	12 words, starting at 0x00000000; last word at 0x0000002C
Initial state	PC = 0x00000000; all registers zero; neither halted nor trapped
Memories	Separate instruction and data memories, 256 KiB each; unlisted data bytes zero

Start address	Bytes, in increasing address order
0x00000100	10 00 00 00
0x00000104	11 00 00 00
0x00000108	12 00 00 00
0x0000010C	13 00 00 00
0x00000110	14 00 00 00
0x00000114	15 00 00 00
0x00000118	16 00 00 00
0x0000011C	17 00 00 00

The table lists the complete preloaded data image, not instruction bytes. Data values use little-endian byte order.

Register	Role established by the program
x1	Next source word address
x2	Next destination word address
x3	Remaining word count
x4	Checksum
x5	Loaded word

The shared setup describes reset, loading, and the behavioral-core selection. These hand-written programs do not use the standard ABI stack.

Assembly

Every instruction word is shown, including words that a trap or branch may prevent from executing. Address and word comments identify the exact fixture image.

addi x1, x0, 0x100             # 0x00000000 | 0x10000093
addi x2, x0, 0x180             # 0x00000004 | 0x18000113
addi x3, x0, 8                 # 0x00000008 | 0x00800193
addi x4, x0, 0                 # 0x0000000C | 0x00000213
loop:
lw x5, 0(x1)                   # 0x00000010 | 0x0000A283
sw x5, 0(x2)                   # 0x00000014 | 0x00512023
add x4, x4, x5                 # 0x00000018 | 0x00520233
addi x1, x1, 4                 # 0x0000001C | 0x00408093
addi x2, x2, 4                 # 0x00000020 | 0x00410113
addi x3, x3, -1                # 0x00000024 | 0xFFF18193
bne x3, x0, loop               # 0x00000028 | 0xFE0194E3
ebreak                         # 0x0000002C | 0x00100073

Execution

1. Initialize source 0x100, destination 0x180, count eight, and checksum zero. Input words are 0x10 through 0x17 (16 through 23).
2. Each pass loads one word, stores it to the destination, adds it to the checksum, advances both pointers by four bytes, decrements the count, and conditionally repeats.
3. Eight copied words occupy 0x180–0x19F. The checksum is 16 + ... + 23 = 156 = 0x9C.
4. Final pointers are 0x120 and 0x1A0; the count is zero. EBREAK makes 4 + 8 × 7 + 1 = 61 attempts.

The checksum remains in x4; the program does not store it after the copied array. Source bytes remain unchanged.

Expected result

These are the fixture's explicit final-state assertions. Unlisted registers are not implicitly zero; their values follow the assembly. The store table enumerates every written byte, including zero-valued writes.

Item	Expected value	Meaning
x1	0x00000120	Next source word address
x2	0x000001A0	Next destination word address
x3	0x00000000	Remaining word count
x4	0x0000009C	Checksum
x5	0x00000017	Loaded word
PC	0x0000002C	EBREAK address
Attempts	61	Checkpoints I0–I60
HALTED	1	Project halt
TRAPPED	0	No exception
TRAP_CAUSE	0	None, a project enum code

Start address	Bytes, in increasing address order
0x00000180	10 00 00 00
0x00000184	11 00 00 00
0x00000188	12 00 00 00
0x0000018C	13 00 00 00
0x00000190	14 00 00 00
0x00000194	15 00 00 00
0x00000198	16 00 00 00
0x0000019C	17 00 00 00

All data bytes not listed as written retain their initial values. This differs from Program 8's byte copy: pointers advance by four, and there is no separate checksum store.

Simulation and checkpoints

For a headless functional check, run build/rv32i_experiment --core single --program 22 --period 4000 --max-cycles 4096 --allocation-limit-mib 512. Select baseline or advanced for the same fixture on another core; add --fidelity reference for the structural-datapath reference profile. The explicit period is a scheduling choice, not a performance result. Use the campaign procedure for clock-certified measurements.

All 61 instruction attempts are included, with absolute simulator time and checkpoint number. The terminating EBREAK is included. The table is scrollable in both directions. Observation conventions distinguish these attempts from loaded word addresses and hardware cycles.

All 61 instruction-attempt checkpoints of RV32ISingleCycleSystemTest/program-22, with a behavioral core. Times are absolute simulator units, not milliseconds or an ISA latency.

Checkpoint	Time	Instruction / address	Expected architectural effects
I0	7080	ADDI @ 0x00000000	raw=0x10000093, pc_after=0x00000004, wb=x1=0x00000100, mem=None, flow=next
I1	11080	ADDI @ 0x00000004	raw=0x18000113, pc_after=0x00000008, wb=x2=0x00000180, mem=None, flow=next
I2	15080	ADDI @ 0x00000008	raw=0x00800193, pc_after=0x0000000c, wb=x3=0x00000008, mem=None, flow=next
I3	19080	ADDI @ 0x0000000c	raw=0x00000213, pc_after=0x00000010, wb=x4=0x00000000, mem=None, flow=next
I4	23080	LW @ 0x00000010	raw=0x0000a283, pc_after=0x00000014, wb=x5=0x00000010, mem=Read Word @0x00000100 -> 0x00000010, flow=next
I5	27080	SW @ 0x00000014	raw=0x00512023, pc_after=0x00000018, wb=None, mem=Write Word @0x00000180 <- 0x00000010, flow=next
I6	31080	ADD @ 0x00000018	raw=0x00520233, pc_after=0x0000001c, wb=x4=0x00000010, mem=None, flow=next
I7	35080	ADDI @ 0x0000001c	raw=0x00408093, pc_after=0x00000020, wb=x1=0x00000104, mem=None, flow=next
I8	39080	ADDI @ 0x00000020	raw=0x00410113, pc_after=0x00000024, wb=x2=0x00000184, mem=None, flow=next
I9	43080	ADDI @ 0x00000024	raw=0xfff18193, pc_after=0x00000028, wb=x3=0x00000007, mem=None, flow=next
I10	47080	BNE @ 0x00000028	raw=0xfe0194e3, pc_after=0x00000010, wb=None, mem=None, branch=BNE taken=true
I11	51080	LW @ 0x00000010	raw=0x0000a283, pc_after=0x00000014, wb=x5=0x00000011, mem=Read Word @0x00000104 -> 0x00000011, flow=next
I12	55080	SW @ 0x00000014	raw=0x00512023, pc_after=0x00000018, wb=None, mem=Write Word @0x00000184 <- 0x00000011, flow=next
I13	59080	ADD @ 0x00000018	raw=0x00520233, pc_after=0x0000001c, wb=x4=0x00000021, mem=None, flow=next
I14	63080	ADDI @ 0x0000001c	raw=0x00408093, pc_after=0x00000020, wb=x1=0x00000108, mem=None, flow=next
I15	67080	ADDI @ 0x00000020	raw=0x00410113, pc_after=0x00000024, wb=x2=0x00000188, mem=None, flow=next
I16	71080	ADDI @ 0x00000024	raw=0xfff18193, pc_after=0x00000028, wb=x3=0x00000006, mem=None, flow=next
I17	75080	BNE @ 0x00000028	raw=0xfe0194e3, pc_after=0x00000010, wb=None, mem=None, branch=BNE taken=true
I18	79080	LW @ 0x00000010	raw=0x0000a283, pc_after=0x00000014, wb=x5=0x00000012, mem=Read Word @0x00000108 -> 0x00000012, flow=next
I19	83080	SW @ 0x00000014	raw=0x00512023, pc_after=0x00000018, wb=None, mem=Write Word @0x00000188 <- 0x00000012, flow=next
I20	87080	ADD @ 0x00000018	raw=0x00520233, pc_after=0x0000001c, wb=x4=0x00000033, mem=None, flow=next
I21	91080	ADDI @ 0x0000001c	raw=0x00408093, pc_after=0x00000020, wb=x1=0x0000010c, mem=None, flow=next
I22	95080	ADDI @ 0x00000020	raw=0x00410113, pc_after=0x00000024, wb=x2=0x0000018c, mem=None, flow=next
I23	99080	ADDI @ 0x00000024	raw=0xfff18193, pc_after=0x00000028, wb=x3=0x00000005, mem=None, flow=next
I24	103080	BNE @ 0x00000028	raw=0xfe0194e3, pc_after=0x00000010, wb=None, mem=None, branch=BNE taken=true
I25	107080	LW @ 0x00000010	raw=0x0000a283, pc_after=0x00000014, wb=x5=0x00000013, mem=Read Word @0x0000010c -> 0x00000013, flow=next
I26	111080	SW @ 0x00000014	raw=0x00512023, pc_after=0x00000018, wb=None, mem=Write Word @0x0000018c <- 0x00000013, flow=next
I27	115080	ADD @ 0x00000018	raw=0x00520233, pc_after=0x0000001c, wb=x4=0x00000046, mem=None, flow=next
I28	119080	ADDI @ 0x0000001c	raw=0x00408093, pc_after=0x00000020, wb=x1=0x00000110, mem=None, flow=next
I29	123080	ADDI @ 0x00000020	raw=0x00410113, pc_after=0x00000024, wb=x2=0x00000190, mem=None, flow=next
I30	127080	ADDI @ 0x00000024	raw=0xfff18193, pc_after=0x00000028, wb=x3=0x00000004, mem=None, flow=next
I31	131080	BNE @ 0x00000028	raw=0xfe0194e3, pc_after=0x00000010, wb=None, mem=None, branch=BNE taken=true
I32	135080	LW @ 0x00000010	raw=0x0000a283, pc_after=0x00000014, wb=x5=0x00000014, mem=Read Word @0x00000110 -> 0x00000014, flow=next
I33	139080	SW @ 0x00000014	raw=0x00512023, pc_after=0x00000018, wb=None, mem=Write Word @0x00000190 <- 0x00000014, flow=next
I34	143080	ADD @ 0x00000018	raw=0x00520233, pc_after=0x0000001c, wb=x4=0x0000005a, mem=None, flow=next
I35	147080	ADDI @ 0x0000001c	raw=0x00408093, pc_after=0x00000020, wb=x1=0x00000114, mem=None, flow=next
I36	151080	ADDI @ 0x00000020	raw=0x00410113, pc_after=0x00000024, wb=x2=0x00000194, mem=None, flow=next
I37	155080	ADDI @ 0x00000024	raw=0xfff18193, pc_after=0x00000028, wb=x3=0x00000003, mem=None, flow=next
I38	159080	BNE @ 0x00000028	raw=0xfe0194e3, pc_after=0x00000010, wb=None, mem=None, branch=BNE taken=true
I39	163080	LW @ 0x00000010	raw=0x0000a283, pc_after=0x00000014, wb=x5=0x00000015, mem=Read Word @0x00000114 -> 0x00000015, flow=next
I40	167080	SW @ 0x00000014	raw=0x00512023, pc_after=0x00000018, wb=None, mem=Write Word @0x00000194 <- 0x00000015, flow=next
I41	171080	ADD @ 0x00000018	raw=0x00520233, pc_after=0x0000001c, wb=x4=0x0000006f, mem=None, flow=next
I42	175080	ADDI @ 0x0000001c	raw=0x00408093, pc_after=0x00000020, wb=x1=0x00000118, mem=None, flow=next
I43	179080	ADDI @ 0x00000020	raw=0x00410113, pc_after=0x00000024, wb=x2=0x00000198, mem=None, flow=next
I44	183080	ADDI @ 0x00000024	raw=0xfff18193, pc_after=0x00000028, wb=x3=0x00000002, mem=None, flow=next
I45	187080	BNE @ 0x00000028	raw=0xfe0194e3, pc_after=0x00000010, wb=None, mem=None, branch=BNE taken=true
I46	191080	LW @ 0x00000010	raw=0x0000a283, pc_after=0x00000014, wb=x5=0x00000016, mem=Read Word @0x00000118 -> 0x00000016, flow=next
I47	195080	SW @ 0x00000014	raw=0x00512023, pc_after=0x00000018, wb=None, mem=Write Word @0x00000198 <- 0x00000016, flow=next
I48	199080	ADD @ 0x00000018	raw=0x00520233, pc_after=0x0000001c, wb=x4=0x00000085, mem=None, flow=next
I49	203080	ADDI @ 0x0000001c	raw=0x00408093, pc_after=0x00000020, wb=x1=0x0000011c, mem=None, flow=next
I50	207080	ADDI @ 0x00000020	raw=0x00410113, pc_after=0x00000024, wb=x2=0x0000019c, mem=None, flow=next
I51	211080	ADDI @ 0x00000024	raw=0xfff18193, pc_after=0x00000028, wb=x3=0x00000001, mem=None, flow=next
I52	215080	BNE @ 0x00000028	raw=0xfe0194e3, pc_after=0x00000010, wb=None, mem=None, branch=BNE taken=true
I53	219080	LW @ 0x00000010	raw=0x0000a283, pc_after=0x00000014, wb=x5=0x00000017, mem=Read Word @0x0000011c -> 0x00000017, flow=next
I54	223080	SW @ 0x00000014	raw=0x00512023, pc_after=0x00000018, wb=None, mem=Write Word @0x0000019c <- 0x00000017, flow=next
I55	227080	ADD @ 0x00000018	raw=0x00520233, pc_after=0x0000001c, wb=x4=0x0000009c, mem=None, flow=next
I56	231080	ADDI @ 0x0000001c	raw=0x00408093, pc_after=0x00000020, wb=x1=0x00000120, mem=None, flow=next
I57	235080	ADDI @ 0x00000020	raw=0x00410113, pc_after=0x00000024, wb=x2=0x000001a0, mem=None, flow=next
I58	239080	ADDI @ 0x00000024	raw=0xfff18193, pc_after=0x00000028, wb=x3=0x00000000, mem=None, flow=next
I59	243080	BNE @ 0x00000028	raw=0xfe0194e3, pc_after=0x0000002c, wb=None, mem=None, branch=BNE taken=false
I60	247080	EBREAK @ 0x0000002c	raw=0x00100073, pc_after=0x0000002c, wb=None, mem=None, flow=next, halted=true

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