frm coverpoints: sweep all 5 fcsr.frm values for dyn rounding mode

Author: dev-aditya-hub

generators/testgen/src/testgen/coverpoints/cp_fp_reg_edges.py

@@ -30,14 +30,28 @@ def make_fs1_edges(instr_name: str, instr_type: str, coverpoint: str, test_data:
 
     cross_frm = "_frm" in coverpoint
 
-    frm_modes = ("dyn", "rdn", "rmm", "rne", "rtz", "rup") if cross_frm else [None]
+    # For dyn we sweep all 5 legal fcsr.frm values explicitly; relying on a random pick
+    # lands on rne 20% of the time and hides a DUT that ignores fcsr.frm.
+    if cross_frm:
+        frm_variants: list[tuple[str | None, int | None]] = [("dyn", v) for v in range(5)]
+        frm_variants += [(m, None) for m in ("rdn", "rmm", "rne", "rtz", "rup")]
+    else:
+        frm_variants = [(None, None)]
 
     test_chunks: list[TestChunk] = []
     for edge_val in edges:
-        for frm_mode in frm_modes:
-            params = generate_random_params(test_data, instr_type, exclude_regs=[0], fs1val=edge_val, frm=frm_mode)
-            bin_name = f"b{edge_val:#x}{f'_{frm_mode}' if frm_mode is not None else ''}"
-            desc = f"{coverpoint} (Test source fs1 value = {test_data.flen_format_str.format(edge_val)}{f', frm = {frm_mode}' if frm_mode is not None else ''})"
+        for frm_mode, csr_val in frm_variants:
+            params = generate_random_params(
+                test_data, instr_type, exclude_regs=[0], fs1val=edge_val, frm=frm_mode, csr_frm_val=csr_val
+            )
+            frm_tag = ""
+            if frm_mode is not None:
+                frm_tag = f"_{frm_mode}{csr_val}" if csr_val is not None else f"_{frm_mode}"
+            bin_name = f"b{edge_val:#x}{frm_tag}"
+            desc_tag = ""
+            if frm_mode is not None:
+                desc_tag = f", frm = {frm_mode}" + (f", fcsr.frm = {csr_val}" if csr_val is not None else "")
+            desc = f"{coverpoint} (Test source fs1 value = {test_data.flen_format_str.format(edge_val)}{desc_tag})"
             tc = format_single_testcase(instr_name, instr_type, test_data, params, desc, bin_name, coverpoint)
             test_chunks.append(tc)
             return_test_regs(test_data, params)

generators/testgen/src/testgen/coverpoints/cp_frm.py

@@ -21,12 +21,22 @@ def make_frm(instr_name: str, instr_type: str, coverpoint: str, test_data: TestD
     if coverpoint not in ["cp_frm_2", "cp_frm_3", "cp_frm_4"]:  # TODO: Why are these variants needed?
         raise ValueError(f"Unknown cp_frm coverpoint variant: {coverpoint} for {instr_name}")
 
-    frm_modes = ("dyn", "rdn", "rmm", "rne", "rtz", "rup")
+    # Static modes encode rm in the instruction. For dyn, rm=111 in the encoding and the
+    # actual rounding comes from fcsr.frm, so we sweep all 5 legal frm values explicitly
+    # rather than relying on a random pick that lands on rne (the power-on default) 20% of
+    # the time and silently agrees with a DUT that ignores fcsr.frm.
+    frm_variants: list[tuple[str, int | None]] = [("dyn", v) for v in range(5)]
+    frm_variants += [(m, None) for m in ("rdn", "rmm", "rne", "rtz", "rup")]
+
     test_chunks: list[TestChunk] = []
-    for frm_mode in frm_modes:
-        params = generate_random_params(test_data, instr_type, exclude_regs=[0], frm=frm_mode)
-        desc = f"{coverpoint} (Test frm, mode = {frm_mode})"
-        tc = format_single_testcase(instr_name, instr_type, test_data, params, desc, f"b{frm_mode}", coverpoint)
+    for frm_mode, csr_val in frm_variants:
+        params = generate_random_params(
+            test_data, instr_type, exclude_regs=[0], frm=frm_mode, csr_frm_val=csr_val
+        )
+        bin_name = f"b{frm_mode}{csr_val}" if csr_val is not None else f"b{frm_mode}"
+        desc_suffix = f", fcsr.frm = {csr_val}" if csr_val is not None else ""
+        desc = f"{coverpoint} (Test frm, mode = {frm_mode}{desc_suffix})"
+        tc = format_single_testcase(instr_name, instr_type, test_data, params, desc, bin_name, coverpoint)
         test_chunks.append(tc)
         return_test_regs(test_data, params)
 

generators/testgen/src/testgen/coverpoints/cr_fp_reg_edges.py

@@ -34,18 +34,29 @@ def make_cr_fs1_fs2_edges(instr_name: str, instr_type: str, coverpoint: str, tes
 
     cross_frm = "_frm" in coverpoint
 
-    frm_modes = ("dyn", "rdn", "rmm", "rne", "rtz", "rup") if cross_frm else [None]
+    # For dyn we sweep all 5 legal fcsr.frm values explicitly rather than picking one
+    # randomly, so a DUT that ignores fcsr.frm can't slip past on the rne case.
+    if cross_frm:
+        frm_variants: list[tuple[str | None, int | None]] = [("dyn", v) for v in range(5)]
+        frm_variants += [(m, None) for m in ("rdn", "rmm", "rne", "rtz", "rup")]
+    else:
+        frm_variants = [(None, None)]
 
     test_chunks: list[TestChunk] = []
     for edge_val1 in edges1:
         for edge_val2 in edges2:
-            # Explicit rounding modes (if needed)
-            for frm_mode in frm_modes:
+            for frm_mode, csr_val in frm_variants:
                 params = generate_random_params(
-                    test_data, instr_type, exclude_regs=[0], fs1val=edge_val1, fs2val=edge_val2, frm=frm_mode
+                    test_data, instr_type, exclude_regs=[0],
+                    fs1val=edge_val1, fs2val=edge_val2,
+                    frm=frm_mode, csr_frm_val=csr_val,
                 )
-                bin_name = f"fs1val={edge_val1:#x}, fs2val={edge_val2:#x}, frm={frm_mode}"
-                desc = f"{coverpoint} (Test source fs1 = {test_data.flen_format_str.format(edge_val1)} fs2 = {test_data.flen_format_str.format(edge_val2)}{f', frm = {frm_mode}' if frm_mode is not None else ''})"
+                frm_label = "none" if frm_mode is None else (f"{frm_mode}{csr_val}" if csr_val is not None else frm_mode)
+                bin_name = f"fs1val={edge_val1:#x}, fs2val={edge_val2:#x}, frm={frm_label}"
+                desc_tag = ""
+                if frm_mode is not None:
+                    desc_tag = f", frm = {frm_mode}" + (f", fcsr.frm = {csr_val}" if csr_val is not None else "")
+                desc = f"{coverpoint} (Test source fs1 = {test_data.flen_format_str.format(edge_val1)} fs2 = {test_data.flen_format_str.format(edge_val2)}{desc_tag})"
                 tc = format_single_testcase(instr_name, instr_type, test_data, params, desc, bin_name, coverpoint)
                 test_chunks.append(tc)
                 return_test_regs(test_data, params)
@@ -71,18 +82,28 @@ def make_cr_fs1_fs3_edges(instr_name: str, instr_type: str, coverpoint: str, tes
 
     cross_frm = "_frm" in coverpoint
 
-    frm_modes = ("dyn", "rdn", "rmm", "rne", "rtz", "rup") if cross_frm else [None]
+    # See note in make_cr_fs1_fs2_edges — dyn is expanded into 5 explicit fcsr.frm values.
+    if cross_frm:
+        frm_variants: list[tuple[str | None, int | None]] = [("dyn", v) for v in range(5)]
+        frm_variants += [(m, None) for m in ("rdn", "rmm", "rne", "rtz", "rup")]
+    else:
+        frm_variants = [(None, None)]
 
     test_chunks: list[TestChunk] = []
     for edge_val1 in edges1:
         for edge_val2 in edges2:
-            # Explicit rounding modes (if needed)
-            for frm_mode in frm_modes:
+            for frm_mode, csr_val in frm_variants:
                 params = generate_random_params(
-                    test_data, instr_type, exclude_regs=[0], fs1val=edge_val1, fs3val=edge_val2, frm=frm_mode
+                    test_data, instr_type, exclude_regs=[0],
+                    fs1val=edge_val1, fs3val=edge_val2,
+                    frm=frm_mode, csr_frm_val=csr_val,
                 )
-                desc = f"{coverpoint} (Test source fs1 = {test_data.flen_format_str.format(edge_val1)} fs3 = {test_data.flen_format_str.format(edge_val2)}{f', frm = {frm_mode}' if frm_mode is not None else ''})"
-                bin_name = f"fs1val={edge_val1:#x}, fs3val={edge_val2:#x}, frm={frm_mode}"
+                frm_label = "none" if frm_mode is None else (f"{frm_mode}{csr_val}" if csr_val is not None else frm_mode)
+                bin_name = f"fs1val={edge_val1:#x}, fs3val={edge_val2:#x}, frm={frm_label}"
+                desc_tag = ""
+                if frm_mode is not None:
+                    desc_tag = f", frm = {frm_mode}" + (f", fcsr.frm = {csr_val}" if csr_val is not None else "")
+                desc = f"{coverpoint} (Test source fs1 = {test_data.flen_format_str.format(edge_val1)} fs3 = {test_data.flen_format_str.format(edge_val2)}{desc_tag})"
                 tc = format_single_testcase(instr_name, instr_type, test_data, params, desc, bin_name, coverpoint)
                 test_chunks.append(tc)
                 return_test_regs(test_data, params)