void UART_put(char *c) {
  unsigned int FiFoCount = 0;
  signed int i = 0;
  while (!((*((volatile unsigned char *)0xE000C014)) & (1 << 6)))
    ;
  while (c[i]) {
    (*((volatile unsigned char *)0xE000C000)) = c[i];
    i++;
    FiFoCount++;
    if (FiFoCount == 16) {
      FiFoCount = 0;
      while (!((*((volatile unsigned char *)0xE000C014)) & (1 << 5)))
        ;
    }
  }
}


x86 assembly (clang, -O0):
<UART_put>:
push   %rbp
mov    %rsp,%rbp
mov    %rdi,-0x8(%rbp)
movl   $0x0,-0xc(%rbp)
movl   $0x0,-0x10(%rbp)
mov    $0xe000c014,%eax
mov    (%rax),%al
movzbl %al,%eax
and    $0x40,%eax
cmp    $0x0,%eax
setne  %al
xor    $0xff,%al
test   $0x1,%al
jne    1138 <UART_put+0x38>
jmp    113d <UART_put+0x3d>
jmp    1116 <UART_put+0x16>
jmp    1142 <UART_put+0x42>
mov    -0x8(%rbp),%rax
movslq -0x10(%rbp),%rcx
cmpb   $0x0,(%rax,%rcx,1)
je     11ba <UART_put+0xba>
mov    -0x8(%rbp),%rax
movslq -0x10(%rbp),%rcx
mov    (%rax,%rcx,1),%cl
mov    $0xe000c000,%eax
mov    %cl,(%rax)
mov    -0x10(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0x10(%rbp)
mov    -0xc(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0xc(%rbp)
cmpl   $0x10,-0xc(%rbp)
jne    11b5 <UART_put+0xb5>
movl   $0x0,-0xc(%rbp)
mov    $0xe000c014,%eax
mov    (%rax),%al
movzbl %al,%eax
and    $0x20,%eax
cmp    $0x0,%eax
setne  %al
xor    $0xff,%al
test   $0x1,%al
jne    11ab <UART_put+0xab>
jmp    11b0 <UART_put+0xb0>
jmp    1189 <UART_put+0x89>
jmp    11b5 <UART_put+0xb5>
jmp    1142 <UART_put+0x42>
pop    %rbp
ret

x86 assembly (clang, -O2):
<UART_put>:
mov    $0xe000c014,%eax
cs nopw 0x0(%rax,%rax,1)
nop
testb  $0x40,(%rax)
je     1110 <UART_put+0x10>
mov    (%rdi),%cl
test   %cl,%cl
je     1159 <UART_put+0x59>
xor    %esi,%esi
xor    %edx,%edx
jmp    1137 <UART_put+0x37>
cs nopw 0x0(%rax,%rax,1)
nopl   0x0(%rax,%rax,1)
mov    (%rdi,%rsi,1),%cl
test   %cl,%cl
je     1159 <UART_put+0x59>
mov    %cl,-0x14(%rax)
add    $0x1,%rsi
add    $0x1,%edx
cmp    $0x10,%edx
jne    1130 <UART_put+0x30>
cs nopw 0x0(%rax,%rax,1)
testb  $0x20,(%rax)
je     1150 <UART_put+0x50>
xor    %edx,%edx
jmp    1130 <UART_put+0x30>
ret

LLVM IR (-O0):
define void @UART_put(i8* %0) {
%2 = alloca i8*
%3 = alloca i32
%4 = alloca i32
store i8* %0, i8** %2
store i32 0, i32* %3
store i32 0, i32* %4
br label %5
5: ; preds = %11, %1
%6 = load volatile i8, i8* inttoptr (i64 3758145556 to i8*)
%7 = zext i8 %6 to i32
%8 = and i32 %7, 64
%9 = icmp ne i32 %8, 0
%10 = xor i1 %9, true
br i1 %10, label %11, label %12
11: ; preds = %5
br label %5
12: ; preds = %5
br label %13
13: ; preds = %41, %12
%14 = load i8*, i8** %2
%15 = load i32, i32* %4
%16 = sext i32 %15 to i64
%17 = getelementptr inbounds i8, i8* %14, i64 %16
%18 = load i8, i8* %17
%19 = icmp ne i8 %18, 0
br i1 %19, label %20, label %42
20: ; preds = %13
%21 = load i8*, i8** %2
%22 = load i32, i32* %4
%23 = sext i32 %22 to i64
%24 = getelementptr inbounds i8, i8* %21, i64 %23
%25 = load i8, i8* %24
store volatile i8 %25, i8* inttoptr (i64 3758145536 to i8*)
%26 = load i32, i32* %4
%27 = add nsw i32 %26, 1
store i32 %27, i32* %4
%28 = load i32, i32* %3
%29 = add i32 %28, 1
store i32 %29, i32* %3
%30 = load i32, i32* %3
%31 = icmp eq i32 %30, 16
br i1 %31, label %32, label %41
32: ; preds = %20
store i32 0, i32* %3
br label %33
33: ; preds = %39, %32
%34 = load volatile i8, i8* inttoptr (i64 3758145556 to i8*)
%35 = zext i8 %34 to i32
%36 = and i32 %35, 32
%37 = icmp ne i32 %36, 0
%38 = xor i1 %37, true
br i1 %38, label %39, label %40
39: ; preds = %33
br label %33
40: ; preds = %33
br label %41
41: ; preds = %40, %20
br label %13
42: ; preds = %13
ret void
}

LLVM IR (-O2):
define void @UART_put(i8* nocapture %0) {
br label %2
2: ; preds = %2, %1
%3 = load volatile i8, i8* inttoptr (i64 3758145556 to i8*)
%4 = and i8 %3, 64
%5 = icmp eq i8 %4, 0
br i1 %5, label %2, label %6
6: ; preds = %2
%7 = load i8, i8* %0
%8 = icmp eq i8 %7, 0
br i1 %8, label %25, label %9
9: ; preds = %6, %20
%10 = phi i64 [ %13, %20 ], [ 0, %6 ]
%11 = phi i8 [ %23, %20 ], [ %7, %6 ]
%12 = phi i32 [ %21, %20 ], [ 0, %6 ]
store volatile i8 %11, i8* inttoptr (i64 3758145536 to i8*)
%13 = add nuw i64 %10, 1
%14 = add i32 %12, 1
%15 = icmp eq i32 %14, 16
br i1 %15, label %16, label %20
16: ; preds = %9, %16
%17 = load volatile i8, i8* inttoptr (i64 3758145556 to i8*)
%18 = and i8 %17, 32
%19 = icmp eq i8 %18, 0
br i1 %19, label %16, label %20
20: ; preds = %16, %9
%21 = phi i32 [ %14, %9 ], [ 0, %16 ]
%22 = getelementptr inbounds i8, i8* %0, i64 %13
%23 = load i8, i8* %22
%24 = icmp eq i8 %23, 0
br i1 %24, label %25, label %9
25: ; preds = %20, %6
ret void
}