CMP (SPC700): Difference between revisions

Latest revision as of 13:54, 30 July 2024


Basic Info
Addressing Mode	Opcode	Length	Speed
Immediate	68	2 bytes	2 cycles
Implied Indirect (type 1)	66	1 bytes	3 cycles
Direct Page	64	2 bytes	3 cycles
Direct Page Indexed by X	74	2 bytes	4 cycles
Absolute	65	3 bytes	4 cycles
Absolute Indexed by X	75	3 bytes	5 cycles
Absolute Indexed by Y	76	3 bytes	5 cycles
Direct Page Indexed Indirect by X	67	2 byte	6 cycles
Direct Page Indirect Indexed by Y	77	2 bytes	6 cycles
Implied Indirect (type 1)	79	1 bytes	5 cycles
Direct Page	69	3 bytes	6 cycles
Direct Page Immediate	78	3 bytes	5 cycles
Immediate	C8	2 bytes	2 cycles
Direct Page	3E	2 bytes	3 cycles
Absolute	1E	3 bytes	4 cycles
Immediate	AD	2 bytes	2 cycles
Direct Page	7E	2 bytes	3 cycles
Absolute	5E	3 bytes	4 cycles


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

CMP is an SPC700 instruction that compares two operands. The right operand is subtracted from the left operand, but the difference is not stored anywhere - the side effect is the N, Z, and C flags being modified.

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.

Syntax

CMP A, #imm
CMP A, (X)
CMP A, dp
CMP A, dp+X
CMP A, !abs
CMP A, !abs+X
CMP A, !abs+Y
CMP A, [dp+X]
CMP A, [dp]+Y
CMP (X), (Y)
CMP dp<d>, dp<s>
CMP dp, #imm
CMP X, dp
CMP X, !abs
CMP Y, #imm
CMP Y, dp
CMP Y, !abs

External Links

Official Super Nintendo development manual on CMP: Table C-7 in Appendix C-5 of Book I
anomie: https://github.com/yupferris/TasmShiz/blob/8fabc9764c33a7ae2520a76d80ed7220bb939f12/spc700.txt#L388

@@ Line 1: / Line 1: @@
-{| class="wikitable" style="float:right;clear:right;width:40%"
+{| class="wikitable" style="float:right;clear:right;width:45%"
 !colspan="8"|Basic Info
 |+
@@ Line 12: / Line 12: @@
 |2 cycles
 |+
-|
+|[[Implied Indirect]] (type 1)
 |66
 |1 bytes
@@ Line 42: / Line 42: @@
 |5 cycles
 |+
-|
+|[[Direct Page Indexed Indirect by X]]
 |67
 |2 byte
 |6 cycles
 |+
-|
+|[[Direct Page Indirect Indexed by Y]]
 |77
 |2 bytes
 |6 cycles
 |+
-|
+|[[Implied Indirect]] (type 1)
 |79
 |1 bytes
@@ Line 100: / Line 100: @@
 {| class="wikitable" style="float:right;clear:right;width:30%"
 !colspan="8"|Flags Affected
+|+
+|[[Negative Flag|N]]
+|[[Overflow Flag|V]]
+|[[Direct Page Flag|P]]
+|[[Break Flag|B]]
+|[[Half-Carry Flag|H]]
+|[[Interrupt Enable Flag|I]]
+|[[Zero Flag|Z]]
+|[[Carry Flag|C]]
 |+
 |N
-|V
-|P
-|B
-|H
-|I
-|Z
-|C
-|+
-|
 |.
 |.
@@ Line 116: / Line 116: @@
 |.
 |.
-|
+|Z
-|
+|C
 |}
 '''CMP''' is an [[SPC700]] instruction that compares two operands.  The right operand is subtracted from the left operand, but the difference is not stored anywhere - the side effect is the N, Z, and C flags being modified.
+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.
+==== Syntax ====
+<pre>
+CMP A, #imm
+CMP A, (X)
+CMP A, dp
+CMP A, dp+X
+CMP A, !abs
+CMP A, !abs+X
+CMP A, !abs+Y
+CMP A, [dp+X]
+CMP A, [dp]+Y
+CMP (X), (Y)
+CMP dp<d>, dp<s>
+CMP dp, #imm
+CMP X, dp
+CMP X, !abs
+CMP Y, #imm
+CMP Y, dp
+CMP Y, !abs
+</pre>
 === See Also ===
 * [[CMPW]]
 * [[CMP]]
+* [[CMP (Super FX)]]
 === External Links ===
-* Official Super Nintendo development manual on CMP: [https://archive.org/details/SNESDevManual/book1/page/n230 Appendix C-5 of Book I]
+* Official Super Nintendo development manual on CMP: Table C-7 in [https://archive.org/details/SNESDevManual/book1/page/n230 Appendix C-5 of Book I]
+* anomie: https://github.com/yupferris/TasmShiz/blob/8fabc9764c33a7ae2520a76d80ed7220bb939f12/spc700.txt#L388
 [[Category:ASM]]
 [[Category:SPC700]]
 [[Category:8-bit Arithmetic Operation Commands]]