Hey y'all --
I was just looking through the disassembly of a project I'm working on around an ARM9 (NXP LPC3250) under the Code Red packaged GCC, and I noticed that all of the floating point code is surrounded by a mess of absolute branches to routines called __vfp11_veneer_N, for various values of N. Each of those routines is nothing but a single floating-point operation, followed by an absolute branch to a return point __vfp11_veneer_N_r, which is always the instruction immediately after the branch. For example:
/* Way up here */
8002978: eeb87a67 vcvt.f32.u32 s14, s15 800297c: eddf7a2d vldr s15, [pc, #180] 8002980: ea0008eb b 8004d34
08002984 : 8002984: eddf7a2c vldr s15, [pc, #176]
/* And way down there */
08004d34 : 8004d34: ee277a27 vmul.f32 s14, s14, s15 8004d38: eafff711 b 8002984
Anyone know what's going on in all of this, why the creation of all these veneer functions, and how I can convince GCC to do otherwise? It almost defeats the purpose of having hardware floating point support if you keep crashing the pipeline to jump to and fro single instruction veneers most (but not all) times you use them.
Thanks, Rob