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GCN ISA MTBUF instructions

These instructions allow to access to images. MIMG instructions operates on the image resources and on the sampler resources.

List of fields for the MIMG encoding:

Bits	Name	Description
8-11	DMASK	Enable mask for read/write data components
12	UNORM	Accepts unnormalized coordinates
13	GLC	Globally coherent
14	DA	Data array (required by array of 1D and 2D images)
15	R128	Image resource size = 128
16	TFE	Texture Fail Enable (for partially resident textures).
17	LWE	LOD Warning Enable (for partially resident textures).
18-24	OPCODE	Operation code
25	SLC	System level coherent
26-31	ENCODING	Encoding type. Must be 0b111100
32-39	VADDR	Vector address operands
40-47	VDATA	Vector data registers
48-52	SRSRC	Scalar registers with buffer resource (SGPR# is 4*value)
53-57	SSAMP	Scalar registers with sampler resource (SGPR# is 4*value)
63	D16	Convert 32-bit data to 16-bit data (GCN 1.2)

Instruction syntax: INSTRUCTION VDATA, VADDR, SRSRC [MODIFIERS]
Instruction syntax: INSTRUCTION VDATA, VADDR, SRSRC, SSAMP [MODIFIERS]

Modifiers can be supplied in any order. Modifiers list: SLC, GLC, TFE, LWE, DA, R128. The TFE flag requires additional the VDATA register.

The MIMG instructions is executed in order. Any MIMG instruction increments VMCNT and it decrements VMCNT after memory operation. Any memory-write operation increments EXPCNT, and it decrements EXPCNT after reading data from VDATA.

Instructions by opcode

List of the MIMG instructions by opcode (GCN 1.0/1.1):

Opcode	GCN 1.0	GCN 1.1	Mnemonic
0 (0x0)	✓	✓	IMAGE_LOAD
1 (0x1)	✓	✓	IMAGE_LOAD_MIP
2 (0x2)	✓	✓	IMAGE_LOAD_PCK
3 (0x3)	✓	✓	IMAGE_LOAD_PCK_SGN
4 (0x4)	✓	✓	IMAGE_LOAD_MIP_PCK
5 (0x5)	✓	✓	IMAGE_LOAD_MIP_PCK_SGN
8 (0x8)	✓	✓	IMAGE_STORE
9 (0x9)	✓	✓	IMAGE_STORE_MIP
10 (0xa)	✓	✓	IMAGE_STORE_PCK
11 (0xb)	✓	✓	IMAGE_STORE_MIP_PCK
14 (0xe)	✓	✓	IMAGE_GET_RESINFO