lswi
Load String Word Immediate - 7C 00 00 4A
lswi
Instruction Syntax
| Mnemonic | Format | Flags |
| lswi | rD,rA,NB | None |
Instruction Encoding
0
1
1
1
1
1
D
D
D
D
D
A
A
A
A
A
N
N
N
N
N
0
0
0
0
0
0
0
0
0
0
0
1
0
0
1
0
1
0
0
0
0
| Field | Bits | Description |
| Primary Opcode | 0-5 | 011111 (0x1F) |
| rD | 6-10 | Starting destination register |
| rA | 11-15 | Base register (can be 0) |
| NB | 16-20 | Number of bytes to load (0-31) |
| XO | 21-30 | 0000000001 (1) - Extended opcode |
| Rc | 31 | Record bit (0) |
Operation
if rA = 0 then EA ← 0
else EA ← (rA)
n ← NB
if n = 0 then n ← 32
for i = 0 to n-1
if i < 4 then
GPR[rD + i] ← MEM(EA + i*4, 4)
else
GPR[((rD + i) mod 32)] ← MEM(EA + i*4, 4)
Words are loaded from consecutive memory locations starting at the effective address. The effective address is the contents of register rA, or zero if rA is 0. The number of words loaded is determined by the NB field: if NB is 0, 32 words are loaded; otherwise, NB words are loaded.
Note: This instruction provides flexible bulk loading with an immediate count. The destination registers wrap around if more than 32 registers would be needed. This instruction is particularly useful for loading variable-length data structures or when the exact number of words to load is known at assembly time.
Affected Registers
- rD through rD+n-1: Loaded with consecutive words from memory (wrapping around if needed)
- rA: Used as base register (if not 0)
Examples
Example 1: Load specific number of words
# Load 8 words starting from r3
lswi r3, r1, 8 # Load 8 words from address in r1Example 2: Load all 32 words
# Load all 32 words (NB = 0)
lswi r0, r2, 0 # Load r0-r31 from address in r2Example 3: Load with register wrapping
# Load 16 words starting from r20
lswi r20, r4, 16 # Load r20-r31, then r0-r3