Add insfd use low part tests.

src/insfd_low.gdb

@@ -0,0 +1,3 @@
+c
+c
+info registers r

src/insfd_low.log

@@ -0,0 +1,15 @@
+Breakpoint 1 at 0x10090
+Breakpoint 2 at 0x100f0
+0x0000000000010078 in _start ()
+
+Breakpoint 1, 0x0000000000010090 in _start ()
+
+Breakpoint 2, 0x00000000000100f0 in _stop ()
+r0                            <10> 0x4afafafa1cccccc0	5402906655116283072
+r1                            <10> 0x4afafafa1ffffff0	5402906655169970160
+r2                            <00> 0x4afafafa1cccccc0	5402906655116283072
+r3                            <00> 0x4afafafa1ffffff0	5402906655169970160
+r4                            <00> 0xc04afafa1ffffff0	13856163155744391152
+r5                            <00> 0xc04afafa1ffffff0	13856163155744391152
+r6                            <00> 0xc04afafa1ffffff0	13856163155744391152
+r7                            <00> 0xc04afafa1ffffff0	13856163155744391152

src/insfd_low.s

@@ -0,0 +1,28 @@
+.global _start
+.global _stop
+
+_start:
+{
+    nop 3
+    setwd wsz=4, nfx=1, dbl=0
+    ldd,sm [ 0 ], %r0
+    ldd,sm [ 0 ], %r1
+}
+{
+    adds 0, 0x1cccccc0, %r0
+    adds 0, 0x1ffffff0, %r1
+}
+{
+    addd 0, 0x4afafafa1cccccc0, %r2
+    addd 0, 0x4afafafa1ffffff0, %r3
+}
+{
+    insfd,0 %r2, (0x0 << 12) | (32 << 6) | 8, %r3, %r4
+    insfd,1 %r0, (0x2 << 12) | (32 << 6) | 8, %r3, %r5
+    insfd,3 %r2, (0x8 << 12) | (32 << 6) | 8, %r1, %r6
+    insfd,4 %r0, (0xa << 12) | (32 << 6) | 8, %r1, %r7
+}
+
+_stop:
+    udivs 0, 0, %empty
+