LDX

Basic Info
Addressing Mode	Opcode	Length	Speed
Immediate	A2	2/3 bytes	2 cycles*
Absolute	AE	3 bytes	4 cycles*
Direct Page	A6	2 bytes	3 cycles*
Absolute Indexed by Y	BE	3 bytes	4 cycles*
Direct Page Indexed by Y	B6	2 bytes	4 cycles*

Flags Affected
N	V	M	X	D	I	Z	C
	.	.	.	.	.		.

LDX (Load X) is a 65x instruction that loads the X index register. In immediate addressing only, LDX is a total of 3 bytes long when the index registers are 16 bits wide.

Syntax

LDX #const
LDX addr
LDX dp
LDX addr, Y
LDX dp, Y

Cycle Penalties

• In direct page addressing modes, LDX takes another extra cycle if the low byte of the direct page register is nonzero.

See Also

• STX
• LDA
• LDY
• TAX
• TYX

External Links

• Eyes & Lichty page 463, on LDX: https://archive.org/details/0893037893ProgrammingThe65816/page/n489
• Labiak page 150 on LDX: https://archive.org/details/Programming_the_65816/page/n160
• MCS6500 Manual page 96 on LDX: https://archive.org/details/mos_microcomputers_programming_manual/page/n114
• https://archive.org/details/mos_microcomputers_programming_manual/page/n219, lbid.
• Carr page 264 on LDX: https://archive.org/details/6502UsersManual/page/n277
• Leventhal page 3-72 on LDX: https://archive.org/details/6502-assembly-language-programming/page/n121
• snes9x implementation of LDX: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L772
• undisbeliever on LDX: https://undisbeliever.net/snesdev/65816-opcodes.html#ldx-load-index-register-x-from-memory