stfd
Store Floating-Point Double - D8 00 00 00
stfd
Instruction Syntax
| Mnemonic | Format | Flags |
| stfd | frS,d(rA) | None |
Instruction Encoding
1
1
0
1
1
0
S
S
S
S
S
A
A
A
A
A
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
| Field | Bits | Description |
| Primary Opcode | 0-5 | 110110 (0x36) |
| frS | 6-10 | Source floating-point register |
| rA | 11-15 | Base register |
| SIMM | 16-31 | Signed immediate offset |
Operation
EA ← (rA) + SIMM (EA) ← (frS)
The effective address is calculated by adding the signed immediate offset to the base register. The double-precision floating-point value in the source register is stored at the effective address.
Note: The stfd instruction stores a 64-bit double-precision floating-point value to memory. The address must be aligned to an 8-byte boundary.
Affected Registers
Memory
- Double-precision floating-point value at effective address (EA)
Examples
Basic Store Floating-Point Double
# Store double-precision value from fr1 to memory stfd fr1, 0(r3) # Store at address in r3 stfd fr1, 8(r3) # Store at address r3 + 8
Array of Doubles
# Store double in array li r4, 0 # Array index slwi r4, r4, 3 # Multiply by 8 (double size) add r5, r3, r4 # Calculate address stfd fr1, 0(r5) # Store double
Floating-Point Calculations
# Store result of floating-point calculation fadd fr2, fr0, fr1 # fr2 = fr0 + fr1 stfd fr2, result # Store result to memory