RISC-V Design · All levels
Compressed ISA and Extension Landscape Overview: Software and Programmer View
Software and Programmer View for Compressed ISA and Extension Landscape Overview.
Software and programmer view
Software and Programmer View for Compressed ISA and Extension Landscape Overview is anchored on Code-size reduction from C extension, extension utilization rate, and performance-per-watt impact by workload segment.. Convert observations into mechanism-backed decisions with explicit ownership.
Keep ISA profile, ABI, and extension assumptions explicit.
Validate runtime feature detection against hardware contract.
Correlate compiler output with microarchitectural counters.
Preserve deterministic trap and privilege behavior in all modes.
Decode contract
diagram
DECODE CONTROL MAP - Compressed ISA and Extension Landscape Overview
opcode/funct3/funct7 controls asserted
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LUI / AUIPC rd_write, imm_select(U), alu_add_pc
JAL / JALR rd_write, pc_redirect, link_write
BRANCH cmp_enable, branch_type, pc_redirect
LOAD mem_read, rd_write, wb_sel(memory)
STORE mem_write, store_size, addr_calc
OP-IMM alu_enable, imm_select(I), rd_write
OP alu_enable, src2_reg, rd_write
SYSTEM / CSR csr_readwrite, trap_check, privilege_gate
VECTOR (V extension) vdecode, lane_mask, vtype_update