b25: S12v2-full + B66-ELF + S16 baked

2026-09-13 12:01:19 +00:00
parent 15eeba929d
commit c875e8712f
4 changed files with 197 additions and 17 deletions
@@ -955,6 +955,95 @@ def main():

    save(d, 'img0_b24.elf')

+    # b25 = b24 + helper-pop S16 chain (0x8007B66 pop{r4,pc} -> bx ip):
+    # the pop reads scratch ([sp+4] = counters 0..4, frames marched by
+    # null-cycles) instead of pushed lr. bx ip uses ip preset by S12
+    # (ARM stub at 0x8006964) to S16 (0x08006CC0, scaffold): restore r7
+    # (peripheral base) and jump to poll-loop resumption 0x8007779.
+    # 2B patch, no eating (bx ip = 0x47c0 fits the pop slot).
+    d = bytearray(base)
+
+    for va, (a, b) in BLX2BL.items():
+
+        set4(d, va, b)
+
+    for va, exp, new in [
+
+        (0x802F664, 'e4f77efc', 'c046c046'),
+
+        (0x802F672, 'e6f7bbfa', 'c046c046'),
+
+        (0x802F678, 'e9f7fef9', 'c046c046'),
+
+        (0x801B71E, '9847fee7', 'c046c046'),
+
+        (0x8008396, 'fef780f9', 'c046c046'),
+
+        (0x8016184, 'fdf790fc', 'c046c046'),
+
+        (0x801B76C, '280b0508', '00000708'),
+
+        (0x8017AFC, 'bde8fc87', 'eef74fb8'),
+
+        (0x802F690, '9847fee7', 'c046c046'),
+
+        (0x801671C, '9847fee7', 'c046c046'),
+
+        (0x8013BAC, 'f8bd0a4a', 'f3f730b8'),
+
+        (0x801B6BE, 'bde8f081', 'ebf7c3ba'),
+
+        (0x8016720, '10bd0000', 'f0f7b2ba'),
+
+    ]:
+
+        assert hx(d, va) == exp, (hex(va), hx(d, va))
+
+        set4(d, va, new)
+
+    # Full bl idiom at 0x8006682 (bl + pop, 6B) -> NOPs (see b18).
+    o = off(0x8006682)
+
+    assert d[o:o + 6].hex() == '00f001f807bd', hx(d, 0x8006682, 6)
+
+    d[o:o + 6] = bytes.fromhex('c046c046c046')
+
+    o = off(0x8013AA8)
+
+    assert d[o:o + 4].hex() == '07f026be', hx(d, 0x8013AA8)
+
+    d[o:o + 4] = bytes.fromhex('c046c046')
+
+    o = off(0x8013BA6)
+
+    assert d[o:o + 2].hex() == 'b888', (hex(0x8013BA6), hx(d, 0x8013BA6, 2))
+
+    d[o:o + 2] = bytes.fromhex('ff20')
+
+    # Logger S8 (see b21).
+    o = off(0x8034810)
+
+    assert d[o:o + 4].hex() == 'bde8fc87', hx(d, 0x8034810)
+
+    d[o:o + 2] = bytes.fromhex('7047')
+
+    # Clock S11 (see b24).
+    o = off(0x800E988)
+
+    assert d[o:o + 2].hex() == '10bd', hx(d, 0x800E988, 2)
+
+    d[o:o + 2] = bytes.fromhex('7047')
+
+    # Helper-pop S16 chain: pop{r4,pc} (2B 10bd) -> bx ip (2B 4760;
+    # ip preset by S12 to S16). 0x47c0 would be bx lr (wrong reg!).
+    o = off(0x8007B66)
+
+    assert d[o:o + 2].hex() == '10bd', hx(d, 0x8007B66, 2)
+
+    d[o:o + 2] = bytes.fromhex('6047')
+
+    save(d, 'img0_b25.elf')
+