Replace .globl with ASM_GLOBAL

[mirror_edk2.git] / MdePkg / Library / BaseLib / Ia32 / DivU64x64Remainder.S

diff --git a/MdePkg/Library/BaseLib/Ia32/DivU64x64Remainder.S b/MdePkg/Library/BaseLib/Ia32/DivU64x64Remainder.S
index df1e6ad495c4028ca19482fdce6dfa96d6d3384a..e87bb77fbc066d794bc7bd6470396f3234fbf983 100644 (file)
--- a/MdePkg/Library/BaseLib/Ia32/DivU64x64Remainder.S
+++ b/MdePkg/Library/BaseLib/Ia32/DivU64x64Remainder.S
@@ -1,6 +1,6 @@
 #------------------------------------------------------------------------------\r
 #\r
-# Copyright (c) 2006, Intel Corporation\r
+# Copyright (c) 2006 - 2008, Intel Corporation\r
 # All rights reserved. This program and the accompanying materials\r
 # are licensed and made available under the terms and conditions of the BSD License\r
 # which accompanies this distribution.  The full text of the license may be found at\r
@@ -11,7 +11,7 @@
 #\r
 # Module Name:\r
 #\r
-#   DivU64x64Remainder.asm\r
+#   DivU64x64Remainder.S\r
 #\r
 # Abstract:\r
 #\r
@@ -20,69 +20,70 @@
 #\r
 #------------------------------------------------------------------------------\r
 \r
+ASM_GLOBAL ASM_PFX(InternalMathDivRemU64x32), ASM_PFX(InternalMathDivRemU64x64)\r
 \r
-\r
-     \r
-\r
-.extern _InternalMathDivRemU64x32\r
-\r
-.global _InternalMathDivRemU64x64\r
-_InternalMathDivRemU64x64: \r
-    movl    16(%esp),%ecx\r
-    testl   %ecx,%ecx\r
-    jnz     _DivRemU64x64\r
-    movl    20(%esp),%ecx\r
+#------------------------------------------------------------------------------\r
+# UINT64\r
+# EFIAPI\r
+# InternalMathDivRemU64x64 (\r
+#   IN      UINT64                    Dividend,\r
+#   IN      UINT64                    Divisor,\r
+#   OUT     UINT64                    *Remainder    OPTIONAL\r
+#   );\r
+#------------------------------------------------------------------------------\r
+ASM_PFX(InternalMathDivRemU64x64):\r
+    movl    16(%esp), %ecx              # ecx <- divisor[32..63]\r
+    testl   %ecx, %ecx\r
+    jnz     Hard                        # call _@DivRemU64x64 if Divisor > 2^32\r
+    movl    20(%esp), %ecx\r
     jecxz   L1\r
-    and     $0,4(%ecx)\r
-    movl    %ecx,16(%esp)\r
-L1: \r
-    jmp     _InternalMathDivRemU64x32\r
-\r
-\r
-.global _DivRemU64x64\r
-_DivRemU64x64:\r
-    push   %ebx                                                                             \r
-    push   %esi                                                                             \r
-    push   %edi                                        \r
+    and     $0, 4(%ecx)                 # zero high dword of remainder\r
+    movl    %ecx, 16(%esp)              # set up stack frame to match DivRemU64x32\r
+L1:\r
+    jmp     ASM_PFX(InternalMathDivRemU64x32)\r
+Hard:\r
+    push    %ebx\r
+    push    %esi\r
+    push    %edi\r
     mov     20(%esp), %edx\r
-    mov     16(%esp), %eax\r
-    movl    %edx,%edi\r
-    movl    %eax,%esi\r
-    mov     24(%esp), %ebx\r
-L2: \r
+    mov     16(%esp), %eax              # edx:eax <- dividend\r
+    movl    %edx, %edi\r
+    movl    %eax, %esi                  # edi:esi <- dividend\r
+    mov     24(%esp), %ebx              # ecx:ebx <- divisor\r
+L2:\r
     shrl    %edx\r
-    rcrl    $1,%eax\r
-    shrdl   $1,%ecx,%ebx\r
+    rcrl    $1, %eax\r
+    shrdl   $1, %ecx, %ebx\r
     shrl    %ecx\r
     jnz     L2\r
     divl    %ebx\r
-    movl    %eax,%ebx\r
-    movl    28(%esp),%ecx\r
-    mull    24(%esp)\r
-    imull   %ebx,%ecx\r
-    addl    %ecx,%edx\r
-    mov     32(%esp), %ecx\r
-    jc      TooLarge\r
-    cmpl    %edx,%edi\r
-    ja      Correct\r
-    jb      TooLarge\r
-    cmpl    %eax,%esi\r
-    jae     Correct\r
-TooLarge: \r
-    decl    %ebx\r
-    jecxz   Return\r
-    sub     24(%esp), %eax\r
-    sbb     28(%esp), %edx\r
-Correct: \r
+    movl    %eax, %ebx                  # ebx <- quotient                     \r
+    movl    28(%esp), %ecx              # ecx <- high dword of divisor        \r
+    mull    24(%esp)                    # edx:eax <- quotient * divisor[0..31]\r
+    imull   %ebx, %ecx                  # ecx <- quotient * divisor[32..63]   \r
+    addl    %ecx, %edx                  # edx <- (quotient * divisor)[32..63] \r
+    mov     32(%esp), %ecx              # ecx <- addr for Remainder           \r
+    jc      TooLarge                    # product > 2^64                      \r
+    cmpl    %edx, %edi                  # compare high 32 bits                \r
+    ja      Correct                                                           \r
+    jb      TooLarge                    # product > dividend                  \r
+    cmpl    %eax, %esi                                                        \r
+    jae     Correct                     # product <= dividend                 \r
+TooLarge:\r
+    decl    %ebx                        # adjust quotient by -1              \r
+    jecxz   Return                      # return if Remainder == NULL        \r
+    sub     24(%esp), %eax                                                   \r
+    sbb     28(%esp), %edx              # edx:eax <- (quotient - 1) * divisor\r
+Correct:\r
     jecxz   Return\r
-    subl    %eax,%esi\r
-    sbbl    %edx,%edi\r
-    movl    %esi,(%ecx)\r
-    movl    %edi,4(%ecx)\r
-Return: \r
-    movl    %ebx,%eax\r
-    xorl    %edx,%edx\r
-    push   %edi                                        \r
-    push   %esi                                                                             \r
-    push   %ebx                                                                             \r
+    subl    %eax, %esi\r
+    sbbl    %edx, %edi                  # edi:esi <- remainder\r
+    movl    %esi, (%ecx)\r
+    movl    %edi, 4(%ecx)\r
+Return:\r
+    movl    %ebx, %eax                  # eax <- quotient         \r
+    xorl    %edx, %edx                  # quotient is 32 bits long\r
+    pop     %edi\r
+    pop     %esi\r
+    pop     %ebx\r
     ret\r