do_explanation(name) char *name;
{
  printf("usage : %s [-t tau0] [-T runTime] [-D dt] [-v vrest] [r RA]\n", name);
  printf("[-L lambda] [-x distance from inj] [-l length] [-d dia] [-i inj] [-n "
         "nterms]\n[-h help]\n");
  printf("Defaults : tau0=%f runTime=%f dt=%e vrest=%f RA=%f\n", 0.04, 0.25,
         50e-6, -0.065, 1.0);
  printf("lambda=%e distance from inj=%e length=%e dia=%e inj=%e nterms=%d\n",
         0.001, 0.001, 0.001, 1.0e-6, 1.0e-10, 10);
  printf("All units in SI == MKSA : metres Kg sec Amps\n");
}


x86 assembly (clang, -O0):
<do_explanation>:
push   %rbp
mov    %rsp,%rbp
sub    $0x10,%rsp
mov    %rdi,-0x10(%rbp)
mov    -0x10(%rbp),%rsi
lea    0xf19(%rip),%rdi
mov    $0x0,%al
call   1030 <printf@plt>
lea    0xf48(%rip),%rdi
mov    $0x0,%al
call   1030 <printf@plt>
lea    0xf92(%rip),%rdi
movsd  0xecd(%rip),%xmm0
movsd  0xecd(%rip),%xmm1
movsd  0xecd(%rip),%xmm2
movsd  0xecd(%rip),%xmm3
movsd  0xecd(%rip),%xmm4
mov    $0x5,%al
call   1030 <printf@plt>
lea    0xf90(%rip),%rdi
movsd  0xe7f(%rip),%xmm2
movsd  0xe7f(%rip),%xmm3
movsd  0xe7f(%rip),%xmm4
mov    $0xa,%esi
movaps %xmm2,%xmm0
movaps %xmm2,%xmm1
mov    $0x5,%al
call   1030 <printf@plt>
lea    0xfa1(%rip),%rdi
mov    $0x0,%al
call   1030 <printf@plt>
mov    -0x4(%rbp),%eax
add    $0x10,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<do_explanation>:
push   %rax
mov    %rdi,%rsi
lea    0xf15(%rip),%rdi
xor    %eax,%eax
call   1040 <printf@plt>
lea    0xfba(%rip),%rdi
call   1030 <puts@plt>
lea    0xf38(%rip),%rdi
movsd  0xeb3(%rip),%xmm0
movsd  0xeb3(%rip),%xmm1
movsd  0xeb3(%rip),%xmm2
movsd  0xeb3(%rip),%xmm3
movsd  0xeb3(%rip),%xmm4
mov    $0x5,%al
call   1040 <printf@plt>
lea    0xf36(%rip),%rdi
movsd  0xea5(%rip),%xmm0
movsd  0xea5(%rip),%xmm3
movsd  0xea5(%rip),%xmm4
movaps %xmm0,%xmm1
movaps %xmm0,%xmm2
mov    $0xa,%esi
mov    $0x5,%al
call   1040 <printf@plt>
lea    0xf9e(%rip),%rdi
pop    %rax
jmp    1030 <puts@plt>

LLVM IR (-O0):
@.str = [61 x i8] c"usage : %s [-t tau0] [-T runTime] [-D dt] [-v vrest] [r RA]\0A\00"
@.str.1 = [88 x i8] c"[-L lambda] [-x distance from inj] [-l length] [-d dia] [-i inj] [-n nterms]\0A[-h help]\0A\00"
@.str.2 = [52 x i8] c"Defaults : tau0=%f runTime=%f dt=%e vrest=%f RA=%f\0A\00"
@.str.3 = [66 x i8] c"lambda=%e distance from inj=%e length=%e dia=%e inj=%e nterms=%d\0A\00"
@.str.4 = [46 x i8] c"All units in SI == MKSA : metres Kg sec Amps\0A\00"
define i32 @do_explanation(i8* %0) {
%2 = alloca i32
%3 = alloca i8*
store i8* %0, i8** %3
%4 = load i8*, i8** %3
%5 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([61 x i8], [61 x i8]* @.str, i64 0, i64 0), i8* %4)
%6 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([88 x i8], [88 x i8]* @.str.1, i64 0, i64 0))
%7 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([52 x i8], [52 x i8]* @.str.2, i64 0, i64 0), double 4.000000e-02, double 2.500000e-01, double 5.000000e-05, double -6.500000e-02, double 1.000000e+00)
%8 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([66 x i8], [66 x i8]* @.str.3, i64 0, i64 0), double 1.000000e-03, double 1.000000e-03, double 1.000000e-03, double 0x3EB0C6F7A0B5ED8D, double 1.000000e-10, i32 10)
%9 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([46 x i8], [46 x i8]* @.str.4, i64 0, i64 0))
%10 = load i32, i32* %2
ret i32 %10
}

LLVM IR (-O2):
@.str = [61 x i8] c"usage : %s [-t tau0] [-T runTime] [-D dt] [-v vrest] [r RA]\0A\00"
@.str.2 = [52 x i8] c"Defaults : tau0=%f runTime=%f dt=%e vrest=%f RA=%f\0A\00"
@.str.3 = [66 x i8] c"lambda=%e distance from inj=%e length=%e dia=%e inj=%e nterms=%d\0A\00"
@str = [87 x i8] c"[-L lambda] [-x distance from inj] [-l length] [-d dia] [-i inj] [-n nterms]\0A[-h help]\00"
@str.5 = [45 x i8] c"All units in SI == MKSA : metres Kg sec Amps\00"
define i32 @do_explanation(i8* %0) {
%2 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([61 x i8], [61 x i8]* @.str, i64 0, i64 0), i8* %0)
%3 = tail call i32 @puts(i8* dereferenceable(1) getelementptr inbounds ([87 x i8], [87 x i8]* @str, i64 0, i64 0))
%4 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([52 x i8], [52 x i8]* @.str.2, i64 0, i64 0), double 4.000000e-02, double 2.500000e-01, double 5.000000e-05, double -6.500000e-02, double 1.000000e+00)
%5 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([66 x i8], [66 x i8]* @.str.3, i64 0, i64 0), double 1.000000e-03, double 1.000000e-03, double 1.000000e-03, double 0x3EB0C6F7A0B5ED8D, double 1.000000e-10, i32 10)
%6 = tail call i32 @puts(i8* dereferenceable(1) getelementptr inbounds ([45 x i8], [45 x i8]* @str.5, i64 0, i64 0))
ret i32 undef
}