feat(v5te): implement THUMB BLX(1), BLX(2), and ARM BLX

src/arm/v5te.zig

@@ -149,6 +149,8 @@ pub const thumb = struct {
         return comptime comptime_blk: {
             @setEvalBranchQuota(5025); // This is exact
             var table = [_]InstrFn{und} ** 0x400;
+            //  9  8  7  6  5  4  3  2  1  0
+            // 15 14 13 12 11 10  9  8  7  6
 
             for (&table, 0..) |*handler, i| {
                 handler.* = switch (@as(u3, i >> 7 & 0x7)) {
@@ -230,12 +232,9 @@ pub const thumb = struct {
                             const cond = i >> 2 & 0xF;
                             break :blk branch.fmt16(InstrFn, cond);
                         },
-                        0b110 => branch.fmt18(
-                            InstrFn,
-                        ),
-                        0b111 => blk: {
-                            const is_low = i >> 5 & 1 == 1;
-                            break :blk branch.fmt19(InstrFn, is_low);
+                        0b110, 0b111 => blk: {
+                            const H = i >> 5 & 0x3;
+                            break :blk branch.linkExchange(InstrFn, H);
                         },
                     },
                 };