LDF: Difference between revisions
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'''LDF''' is an assembly instruction. The contents of the [[effective address]] and the two following locations ared loaded into the [[floating accumulator]], i.e. T, A and D registers. The instruction always load the three registers, even in CPUs with the [[32-bit floating point]] option. With 32-bit floating point units the application must use the [[LDD]] doubleword instruction instead | '''LDF''' is an assembly instruction. The contents of the [[effective address]] and the two following locations ared loaded into the [[floating accumulator]], i.e. T, A and D registers. The instruction always load the three registers, even in CPUs with the [[32-bit floating point]] option. With 32-bit floating point units the application must use the [[LDD]] doubleword instruction instead of LDF. [[MAC]] programmers may use the MAC mnemonic [[LDR]] instead, which will translate to LDF or LDD depending on target. | ||
LDF is also used as a generic 3-word load function, and applications may use LDF with [[STF]] to copy 3 words at the time with no floating point operation performed on the floating point accumulator. This usage is independent of which floating point option the CPU is equipped with. | LDF is also used as a generic 3-word load function, and applications may use LDF with [[STF]] to copy 3 words at the time with no floating point operation performed on the floating point accumulator. This usage is independent of which floating point option the CPU is equipped with. | ||
Latest revision as of 14:29, 30 June 2010
| LDF | |
|---|---|
| Description | Load floating accumulator |
| Format | LDF <addr. mode> <disp.> |
| Code | 034 0008 |
| Affected | T:=(ea) A=(ea+1) D=(ea+2) |
| Type | User |
| Architecture | ND-100, ND-110 |
LDF is an assembly instruction. The contents of the effective address and the two following locations ared loaded into the floating accumulator, i.e. T, A and D registers. The instruction always load the three registers, even in CPUs with the 32-bit floating point option. With 32-bit floating point units the application must use the LDD doubleword instruction instead of LDF. MAC programmers may use the MAC mnemonic LDR instead, which will translate to LDF or LDD depending on target.
LDF is also used as a generic 3-word load function, and applications may use LDF with STF to copy 3 words at the time with no floating point operation performed on the floating point accumulator. This usage is independent of which floating point option the CPU is equipped with.
References
- Norsk Data Document ND–06.014.02 ND-100 REFERENCE MANUAL Page 3-20
- Norsk Data Document ND–06.029.01 ND-110 Instruction Set Page 60
- Norsk Data Document ND–60.096.01 MAC INTERACTIVE ASSEMBLY AND DEBUGGING SYSTEM USER'S GUIDE Appendix E