DAS (SPC700): Difference between revisions

Revision as of 19:41, 22 July 2023


Basic Info
Addressing Mode	Opcode	Length	Speed
implied	BE	1 byte	3 cycles


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

DAS (Decimal Adjust for Subtraction) is an SPC700 instruction that performs the following:

If either the carry flag is clear or the accumulator exceeds 0x99, 0x60 is subtracted from the accumulator and the carry flag is cleared.
Then, if either the half-carry flag is clear or the low nibble of the accumulator exceeds 0x09, 0x06 is subtracted from the accumulator

@@ Line 35: / Line 35: @@
 |}
-'''DAS''' (Decimal Adjust for Subtraction) is an [[SPC700]] instruction.
+'''DAS''' (Decimal Adjust for Subtraction) is an [[SPC700]] instruction that performs the following:
+# If either the [[carry flag]] is clear or the accumulator exceeds 0x99, 0x60 is subtracted from the accumulator and the carry flag is cleared.
+# Then, if either the [[half-carry flag]] is clear or the low nibble of the accumulator exceeds 0x09, 0x06 is subtracted from the accumulator
 === See Also ===
@@ Line 44: / Line 46: @@
 * Official Super Nintendo development manual on DAS: [https://archive.org/details/SNESDevManual/book1/page/n233 Appendix C-8 of Book I]
 * [https://archive.org/details/SNESDevManual/book1/page/n180 page 3-8-2 of Book I], lbid
+* ares source code, SPC700::instructionDecimalAdjustSub
 [[Category:ASM]]
 [[Category:SPC700]]
 [[Category:Decimal Compensation Commands]]