Claudeでデータシートのレジスタ表をC構造体に変換 — リセット値の照合まで

添付PDFの p.40-44 から TMR0 のレジスタを JSON に起こしてください。
- レジスタごとに name / offset / page / summary_reset(一覧表のリセット値)
- フィールドごとに name / msb / lsb / reset(詳細表のリセット値)
- フィールドごとに access(RO / RW / W1C など、PDFの属性欄の表記どおり)
- Reserved の行は fields に入れない
- 読み取れない値、表をまたいで途切れた行は、推測せず "unknown" と書く
- アドレスマップの表は address_map に別で写す

{
  "peripheral": "TMR0",
  "base": "0x40001000",
  "registers": [
    {"name": "CTRL", "offset": "0x00", "page": 41, "summary_reset": "0x00000040",
     "fields": [
       {"name": "EN",    "msb": 0,  "lsb": 0, "reset": "0x0", "access": "RW"},
       {"name": "MODE",  "msb": 2,  "lsb": 1, "reset": "0x0", "access": "RW"},
       {"name": "IRQEN", "msb": 3,  "lsb": 3, "reset": "0x0", "access": "RW"},
       {"name": "PRESC", "msb": 11, "lsb": 4, "reset": "0x04", "access": "RW"}]},
    {"name": "STAT", "offset": "0x04", "page": 42, "summary_reset": "0x00000000",
     "fields": [
       {"name": "BUSY", "msb": 0, "lsb": 0, "reset": "0x0", "access": "RO"},
       {"name": "OVF",  "msb": 1, "lsb": 1, "reset": "0x0", "access": "W1C"}]},
    {"name": "LOAD", "offset": "0x08", "page": 42, "summary_reset": "0x0000FFFF",
     "fields": [
       {"name": "VALUE", "msb": 15, "lsb": 0, "reset": "0xFFFF", "access": "RW"}]},
    {"name": "CNT",  "offset": "0x10", "page": 43, "summary_reset": "0x00000000",
     "fields": [
       {"name": "VALUE", "msb": 15, "lsb": 0, "reset": "0x0", "access": "RO"}]}
  ],
  "address_map": {"CTRL": "0x40001000", "STAT": "0x40001004",
                  "LOAD": "0x40001008", "CNT": "0x40001010"}
}

import json, sys
 
spec = json.load(open(sys.argv[1]))
base = int(spec["base"], 16)
errors = []
prev_offset = -4
 
for reg in spec["registers"]:
    name, off = reg["name"], int(reg["offset"], 16)
    if off <= prev_offset or off % 4:
        errors.append(f"{name}: オフセット {off:#x} が昇順でない/4の倍数でない")
    prev_offset = off
 
    used, composed = 0, 0
    for f in reg["fields"]:
        width = f["msb"] - f["lsb"] + 1
        if width < 1:
            errors.append(f"{name}.{f['name']}: msb<lsb ({f['msb']}:{f['lsb']})")
            continue
        mask = ((1 << width) - 1) << f["lsb"]
        if used & mask:
            errors.append(f"{name}.{f['name']}: 他フィールドとビットが重なる")
        used |= mask
        value = int(f["reset"], 16)
        if value >> width:
            errors.append(f"{name}.{f['name']}: リセット値 {f['reset']} が{width}ビットに入らない")
        composed |= (value << f["lsb"]) & mask
 
    summary = int(reg["summary_reset"], 16)
    if composed != summary:
        errors.append(f"{name}: フィールド合成 {composed:#010x} != 一覧表 {summary:#010x} (p.{reg['page']})")
 
    addr = int(spec["address_map"][name], 16)
    if addr != base + off:
        errors.append(f"{name}: base+offset {base + off:#x} != アドレスマップ {addr:#x}")
 
print("\n".join(errors) or "OK")
sys.exit(1 if errors else 0)

CTRL: フィールド合成 0x00000080 != 一覧表 0x00000040 (p.41)

CNT: base+offset 0x40001010 != アドレスマップ 0x4000100c

import json, sys
 
spec = json.load(open(sys.argv[1]))
p = spec["peripheral"]
out = ["#include <stdint.h>", "#include <stddef.h>", ""]
for reg in spec["registers"]:
    pos, lines = 0, []
    for f in sorted(reg["fields"], key=lambda f: f["lsb"]):
        if f["lsb"] > pos:
            lines.append(f"    uint32_t _rsvd{pos} : {f['lsb'] - pos};")
        lines.append(f"    uint32_t {f['name']} : {f['msb'] - f['lsb'] + 1};")
        pos = f["msb"] + 1
    if pos < 32:
        lines.append(f"    uint32_t _rsvd{pos} : {32 - pos};")
    out += ["typedef union {", "    uint32_t raw;", "    struct {",
            *["    " + l for l in lines], "    } f;",
            f"}} {p}_{reg['name']}_t;", ""]
out.append("typedef struct {")
cursor = 0
for reg in spec["registers"]:
    off = int(reg["offset"], 16)
    if off > cursor:
        out.append(f"    uint32_t _gap{cursor:02X}[{(off - cursor) // 4}];")
    out.append(f"    volatile {p}_{reg['name']}_t {reg['name']};")
    cursor = off + 4
out += [f"}} {p}_regs_t;", ""]
for reg in spec["registers"]:
    out.append(f'_Static_assert(offsetof({p}_regs_t, {reg["name"]}) == {reg["offset"]}, '
               f'"{p}.{reg["name"]} offset");')
print("\n".join(out))

typedef union {
    uint32_t raw;
    struct {
        uint32_t EN : 1;
        uint32_t MODE : 2;
        uint32_t IRQEN : 1;
        uint32_t PRESC : 8;
        uint32_t _rsvd12 : 20;
    } f;
} TMR0_CTRL_t;

#include <stdio.h>
#include "tmr0_regs.h"
 
int main(void) {
    int bad = 0;
    { TMR0_CTRL_t r = { .f = { .EN = 0x0, .MODE = 0x0, .IRQEN = 0x0, .PRESC = 0x04 } };
      if (r.raw != 0x00000040u) { printf("NG CTRL: %08x\n", (unsigned)r.raw); bad++; } }
    { TMR0_LOAD_t r = { .f = { .VALUE = 0xFFFF } };
      if (r.raw != 0x0000FFFFu) { printf("NG LOAD: %08x\n", (unsigned)r.raw); bad++; } }
    /* STAT・CNT も同じ形。仕様データから生成する */
    puts(bad ? "FAIL" : "PASS");
    return bad != 0;
}

import json, sys
 
spec = json.load(open(sys.argv[1]))
p = spec["peripheral"]
print(f'#include <stdio.h>\n#include "tmr0_regs.h"\nint main(void) {{ int bad = 0;')
for reg in spec["registers"]:
    init = ", ".join(f'.{f["name"]} = {f["reset"]}' for f in reg["fields"])
    t = f'{p}_{reg["name"]}_t'
    print(f'  {{ {t} r = {{ .f = {{ {init} }} }};')
    print(f'    if (r.raw != {reg["summary_reset"]}u) {{ printf("NG {reg["name"]}: %08x\\n", (unsigned)r.raw); bad++; }} }}')
print('  puts(bad ? "FAIL" : "PASS"); return bad != 0; }')

NG CTRL: 00000080
FAIL

# レジスタ定義のルール
- レジスタ表は tmr0.json に起こし、構造体を手で書かない
- 読み取れない値は "unknown" にし、推測で埋めない
- 変更後は check_spec.py から ./t までを実行し、PASS を確認してから報告する
- 検査が落ちたら、仕様データの該当ページ(page)を読み直して原因を直す