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ASL: Difference between revisions
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{| class="wikitable" style="float:right;clear:right;width:40%" | |||
{| class="wikitable" style="float:right;clear:right;width: | |||
!colspan="8"|Basic Info | !colspan="8"|Basic Info | ||
|+ | |+ | ||
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|'''Speed''' | |'''Speed''' | ||
|+ | |+ | ||
| | |[[Accumulator Addressing|Accumulator]] | ||
|0A | |0A | ||
|1 byte | |1 byte | ||
|2 cycles | |2 cycles | ||
|+ | |+ | ||
| | |[[Absolute]] | ||
|0E | |0E | ||
|3 bytes | |3 bytes | ||
|6 cycles | |6 cycles* | ||
|+ | |+ | ||
| | |[[Direct Page Addressing|Direct Page]] | ||
|06 | |06 | ||
|2 bytes | |2 bytes | ||
|5 cycles | |5 cycles* | ||
|+ | |+ | ||
|absolute indexed X | |absolute indexed X | ||
|1E | |1E | ||
|3 bytes | |3 bytes | ||
|7 cycles | |7 cycles* | ||
|+ | |+ | ||
|direct page indexed X | |direct page indexed X | ||
|16 | |16 | ||
|2 bytes | |2 bytes | ||
|6 cycles | |6 cycles* | ||
|} | |} | ||
{| class="wikitable" style="width:30%" | {| class="wikitable" style="float:right;clear:right;width:30%" | ||
!colspan="9"|Flags | !colspan="9"|Flags Affected | ||
|+ | |+ | ||
|N | |[[N Flag|N]] | ||
|V | |[[V Flag|V]] | ||
|M | |[[M Flag|M]] | ||
|X | |[[X Flag|X]] | ||
|D | |[[D Flag|D]] | ||
|I | |[[I Flag|I]] | ||
|Z | |[[Z Flag|Z]] | ||
|C | |[[C Flag|C]] | ||
|+ | |+ | ||
| | | | ||
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'''ASL''' (Arithmetic Shift Left) is a 65x instruction that shifts a value by left one bit (multiplication by two). The most significant bit is shifted into the [[carry flag]]. The least significant bit becomes a zero. | |||
===== Cycle Penalties ===== | |||
* Except in [[accumulator addressing]], ASL takes two extra cycles when the accumulator is 16 bits wide | |||
* In [[direct page addressing]] modes, ASL takes another extra cycle if the low byte of the [[direct page register]] is nonzero. | |||
=== See Also === | |||
* [[LSR]] | |||
* [[ASL (SPC700)]] | |||
=== External Links === | === External Links === | ||
* [[Eyes & Lichty]] page on ASL: https://archive.org/details/0893037893ProgrammingThe65816/page/n453 | * [[Eyes & Lichty]] page 427, on ASL: https://archive.org/details/0893037893ProgrammingThe65816/page/n453 | ||
* lbid page 190, before & after diagram of ASL: https://archive.org/details/0893037893ProgrammingThe65816/page/n216 | |||
* [[Labiak]] page 117 on ASL: https://archive.org/details/Programming_the_65816/page/n127 | |||
* [[MCS6500 Manual]] page 149 on ASL: https://archive.org/details/mos_microcomputers_programming_manual/page/n170 | |||
* https://archive.org/details/mos_microcomputers_programming_manual/page/n205 | |||
* [[Carr]] page 247 on ASL: https://archive.org/details/6502UsersManual/page/n260 | |||
* [[Leventhal]] page 3-41 on ASL: https://archive.org/details/6502-assembly-language-programming/page/n90 | |||
* undisbeliever on ASL: https://undisbeliever.net/snesdev/65816-opcodes.html#asl-arithmetic-shift-left | |||
[[Category:ASM]] | [[Category:ASM]] |
Latest revision as of 10:42, 19 December 2023
Basic Info | |||||||
---|---|---|---|---|---|---|---|
Addressing Mode | Opcode | Length | Speed | ||||
Accumulator | 0A | 1 byte | 2 cycles | ||||
Absolute | 0E | 3 bytes | 6 cycles* | ||||
Direct Page | 06 | 2 bytes | 5 cycles* | ||||
absolute indexed X | 1E | 3 bytes | 7 cycles* | ||||
direct page indexed X | 16 | 2 bytes | 6 cycles* |
Flags Affected | ||||||||
---|---|---|---|---|---|---|---|---|
N | V | M | X | D | I | Z | C | |
. | . | . | . | . |
ASL (Arithmetic Shift Left) is a 65x instruction that shifts a value by left one bit (multiplication by two). The most significant bit is shifted into the carry flag. The least significant bit becomes a zero.
Cycle Penalties
- Except in accumulator addressing, ASL takes two extra cycles when the accumulator is 16 bits wide
- In direct page addressing modes, ASL takes another extra cycle if the low byte of the direct page register is nonzero.
See Also
External Links
- Eyes & Lichty page 427, on ASL: https://archive.org/details/0893037893ProgrammingThe65816/page/n453
- lbid page 190, before & after diagram of ASL: https://archive.org/details/0893037893ProgrammingThe65816/page/n216
- Labiak page 117 on ASL: https://archive.org/details/Programming_the_65816/page/n127
- MCS6500 Manual page 149 on ASL: https://archive.org/details/mos_microcomputers_programming_manual/page/n170
- https://archive.org/details/mos_microcomputers_programming_manual/page/n205
- Carr page 247 on ASL: https://archive.org/details/6502UsersManual/page/n260
- Leventhal page 3-41 on ASL: https://archive.org/details/6502-assembly-language-programming/page/n90
- undisbeliever on ASL: https://undisbeliever.net/snesdev/65816-opcodes.html#asl-arithmetic-shift-left