Mnemonic
| LDS |
Description
This instruction sets or resets the carry and overflow indicators. Bits 14 and 15 of the instruction set or reset the indicators as follows:
| Set or Reset | |||
|---|---|---|---|
| Bit 14 | Bit 15 | Carry Indicator | Overflow Indicator |
| 0 | 0 | reset (=0) | reset (=0) |
| 0 | 1 | reset (=0) | set (=1) |
| 1 | 0 | Set (=1) | reset (=0) |
| 1 | 1 | set (=1) | set (=1) |
This instruction is not valid in the long format. If an attempt is made to execute a load-status instruction in which the F bit = 1, the instruction is still treated as a short-format instruction by the system.
A load-status instruction is usually the core-storage word addressed by a store-status instruction. The load-status instruction is subsequently executed before a return to the routine originally interrupted — the routine whose status was stored by the store-status instruction.
Core storage is not addressed as a result of execution of a load-status instruction.
Indicators: The carry and overflow indicators are affected as described under the description of this instruction.
Examples
Load Status
| Assembler Language Coding | Hexadecimal Value | Description of Instruction | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Label | Operation | F | T | ||||||||
|
|
32 | 33 | 35..40.. | |||||||
| LDS | 0 | 2000 | Set CARRY and OVERFLOW indicators OFF | ||||||||
| LDS | 1 | 2001 | SET OVERFLOW ON and CARRY OFF | ||||||||
| LDS | 2 | 2002 | Set OVERFLOW OFF and CARRY ON | ||||||||
| LDS | 3 | 2003 | SET CARRY and OVERFLOW indicator ON | ||||||||
Intentionally Blank
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