s_sub_co_u32 GPU Native ISA AMD Scalar

Scalar Arithmetic

s_sub_co_u32

Subtract the second unsigned 32-bit integer input from the first input, store the result into a scalar register and store the carry-out bit into SCC.

Also written as s_sub_u32. AMD's machine-readable ISA specification lists this name for the same instruction.

Encoding

Binary Layout (AMD CDNA 5)
10
31:30
0000001
29:23
SDST
22:16
SSRC1
15:8
SSRC0
7:0
 

The ENC_SOP2 layout from AMD's machine-readable ISA specification (AMD CDNA 5). Opcode 1 in OP rebuilds 0x80800000, an identifier AMD lists for this encoding. The same in AMD RDNA 4.

Format SOP2
Width 32 bits
Opcode 1
Identifier 0x80800000

Operands

  • SDST
    Written. All scalar destination operands. Data format: Unsigned 32-bit integral data. (OPR_SDST, FMT_NUM_U32)
  • SSRC0
    Read. All scalar operands. Covers all operands that are allowed as scalar sources. Data format: Unsigned 32-bit integral data. (OPR_SSRC, FMT_NUM_U32)
  • SSRC1
    Read. All scalar operands. Covers all operands that are allowed as scalar sources. Data format: Unsigned 32-bit integral data. (OPR_SSRC, FMT_NUM_U32)

In AMD's order, as its machine-readable ISA specification lists them for the ENC_SOP2 encoding (AMD CDNA 5).

GFX Target Compatibility

TargetSupport
gfx1100✅ Supported

Related

More in Scalar Arithmetic

Reference

AMDGPU / GFX ISA

Example

s_sub_co_u32 s0, 0, s2

A real instruction accepted by the LLVM assembler, taken verbatim from LLVM's own AMDGPU MC test suite (gfx12_asm_sop2.s). Not from an AMD document, and not authored here.

Sources