OR1 (SPC700): Difference between revisions

Latest revision as of 14:08, 30 July 2024


Basic Info
Addressing Mode	Opcode	Length	Speed
Absolute Boolean Bit	0A	3 bytes	5 cycles
Absolute Boolean Bit	2A	3 bytes	5 cycles


Flags Affected
N	V	P	B	H	I	Z	C
.	.	.	.	.	.	.	C

OR1 is an SPC700 instruction that performs a logical or between a memory bit and the carry flag, then stores the disjunction in the carry flag. The low 13 bits of the operand byte specify an absolute address. The high 3 bits of the operand byte specify which bit at that absolute address.

The bit reversal operator may be prefixed to the memory bit address, in which case opcode 2A is assembled.

Syntax

OR1 C, mem. bit
OR1 C, /mem. bit

External Links

Official Super Nintendo development manual on OR1: Appendix C-9 of Book I
subparagraph 8.2.3.3 of page 3-8-8, lbid.
anomie: https://github.com/yupferris/TasmShiz/blob/master/spc700.txt#L531

@@ Line 7: / Line 7: @@
 |'''Speed'''
 |+
-|[[13-bit Absolute]]
+|[[Absolute Boolean Bit]]
 |0A
 |3 bytes
 |5 cycles
 |+
-|[[13-bit Absolute]]
+|[[Absolute Boolean Bit]]
 |2A
 |3 bytes
@@ Line 37: / Line 37: @@
 |.
 |.
-|
+|C
 |}
 '''OR1''' is an [[SPC700]] instruction that performs a logical or between a memory bit and the [[carry flag]], then stores the disjunction in the carry flag.  The low 13 bits of the operand byte specify an absolute address.  The high 3 bits of the operand byte specify which bit at that absolute address.
-The operands are stored in the instruction stream in the opposite order they appear in the assembler source. In the assembler source, the operand on the right is the source and the operand on the left is the destination.
+The [[bit reversal]] operator may be prefixed to the memory bit address, in which case opcode 2A is assembled.
+==== Syntax ====
+<pre>
+OR1 C, mem. bit
+OR1 C, /mem. bit
+</pre>
 === See Also ===
@@ Line 49: / Line 55: @@
 * [[EOR1]]
 * [[MOV1]]
+* [[NOT1]]
 === External Links ===
 * Official Super Nintendo development manual on OR1: [https://archive.org/details/SNESDevManual/book1/page/n234 Appendix C-9 of Book I]
-* [https://archive.org/details/SNESDevManual/book1/page/n186 page 3-8-8], lbid.
+* subparagraph 8.2.3.3 of [https://archive.org/details/SNESDevManual/book1/page/n186 page 3-8-8], lbid.
+* anomie: https://github.com/yupferris/TasmShiz/blob/master/spc700.txt#L531
 [[Category:ASM]]