Texas Instruments TMS320C67X/C67X+ DSP manual Tion operates only on the .D2 unit

LDH(U) Load Halfword From Memory With a 15-Bit Unsigned Constant Offset

				Load Halfword From Memory With a 15-Bit Unsigned Constant Offset
LDH(U)
Syntax					LDH (.unit) *+B14/B15[ucst15], dst
					or
					LDHU (.unit) *+B14/B15[ucst15], dst
					.unit = .D2
Compatibility					C62x, C64x, C67x, and C67x+ CPU
Opcode
31	29	28	27	23		22	18	17	13	12	9	8	7	6	4	3	2	1	0

creg

z

dst

ucst15

y

op

1 1 s p

3 1 5 15 1 3 1 1

Description	Loads a halfword from memory to a general-purpose register (dst). Table 3−20
	summarizes the data types supported by loads. The memory address is
	formed from a base address register B14 (y = 0) or B15 (y = 1) and an offset,
	which is a 15-bit unsigned constant (ucst15). The assembler selects this for-
	mat only when the constant is larger than five bits in magnitude. This instruc-
	tion operates only on the .D2 unit.
	The offset, ucst15, is scaled by a left shift of 1 bit. After scaling, ucst15 is added
	to baseR. Subtraction is not supported. The result of the calculation is the
	address sent to memory. The addressing arithmetic is always performed in
	linear mode.
	For LDH(U), the values are loaded into the 16 LSBs of dst. For LDH, the upper
	16 bits of dst are sign-extended; for LDHU, the upper 16 bits of dst are zero-
	filled. The s bit determines which file dst will be loaded into: s = 0 indicates dst
	will be loaded in the A register file and s = 1 indicates dst will be loaded in the
	B register file.
	Square brackets, [ ], indicate that the ucst15 offset is left-shifted by 1.
	Parentheses, ( ), can be used to set a nonscaled, constant offset. You must
	type either brackets or parentheses around the specified offset, if you use the
	optional offset parameter.
	Halfword addresses must be aligned on halfword (LSB is 0) boundaries.

3-134 Instruction Set SPRU733