Changes in boot/arch/ppc32/src/asm.S [0dd8c29:b372015] in mainline

File:

• boot/arch/ppc32/src/asm.S (modified) (2 diffs)

boot/arch/ppc32/src/asm.S

@@ -58 +58 @@
 .endm
 
+.macro BAT_COMPUTE base size mask lower upper
+        # less than 128 KB -> no BAT
+        
+        lis \upper, 0x0002
+        cmpw \size, \upper
+        blt no_bat
+        
+        # mask = total >> 18
+        
+        li \upper, 18
+        srw \mask, \size, \upper
+        
+        # create Block Length mask by replicating
+        # the leading logical one 14 times
+        
+        li \upper, 14
+        mtctr \mask
+        li \upper, 1
+        
+        0:
+                # mask = (mask >> 1) | mask
+                
+                srw \lower, \mask, \upper
+                or \mask, \mask, \lower
+                
+                bdnz 0b
+        
+        # mask = mask & 0x07ff
+        # (BAT can map up to 256 MB)
+        
+        andi. \mask, \mask, 0x07ff
+        
+        # mask = (mask << 2) | 0x0002
+        # (priviledged access only)
+        
+        li \upper, 2
+        slw \mask, \mask, \upper
+        ori \mask, \mask, 0x0002
+        
+        lis \upper, (0x8000 + \base)
+        or \upper, \upper, \mask
+        
+        lis \lower, \base
+        ori \lower, \lower, 0x0002
+.endm
+
 .global start
 .global halt
@@ -247 +293 @@
         lwz r31, 4(r3)                # r31 = memory size
         
-        lis r29, 0x0002
-        cmpw r31, r29
-        blt no_bat                    # less than 128 KB -> no BAT
-        
-        li r29, 18
-        srw r31, r31, r29             # r31 = total >> 18
-        
-        # create Block Length mask by replicating
-        # the leading logical one 14 times
-        
-        li r29, 14
-        mtctr r31
-        li r29, 1
-        
-        bat_mask:
-                srw r30, r31, r29         # r30 = mask >> 1
-                or r31, r31, r30          # mask = mask | r30
-                
-                bdnz bat_mask
-        
-        andi. r31, r31, 0x07ff        # mask = mask & 0x07ff (BAT can map up to 256 MB)
-        
-        li r29, 2
-        slw r31, r31, r29             # mask = mask << 2
-        ori r31, r31, 0x0002          # mask = mask | 0x0002 (priviledged access only)
-        
-        lis r29, 0x8000
-        or r29, r29, r31
-        
-        lis r30, 0x0000
-        ori r30, r30, 0x0002
-        
-        mtspr ibat0u, r29
-        mtspr ibat0l, r30
-        
-        mtspr dbat0u, r29
-        mtspr dbat0l, r30
+        lis r30, 268435456@h
+        ori r30, r30, 268435456@l     # r30 = 256 MB
+        
+        # BAT0
+        
+        # r29 = min(r31, r30)
+        
+        cmpw r31, r30
+        blt bat0_r31
+        
+                mr r29, r30
+                b bat0_r30
+        
+        bat0_r31:
+        
+                mr r29, r31
+        
+        bat0_r30:
+        
+        BAT_COMPUTE 0x0000 r29 r28 r27 r26
+        mtspr ibat0u, r26
+        mtspr ibat0l, r27
+        
+        mtspr dbat0u, r26
+        mtspr dbat0l, r27
+        
+        # BAT1
+        
+        sub r31, r31, r29             # r31 = r31 - r29
+        
+        # r29 = min(r31, r30)
+        
+        cmpw r31, r30
+        blt bat1_r31
+        
+                mr r29, r30
+                b bat1_r30
+        
+        bat1_r31:
+        
+                mr r29, r31
+        
+        bat1_r30:
+        
+        BAT_COMPUTE 0x1000 r29 r28 r27 r26
+        mtspr ibat1u, r26
+        mtspr ibat1l, r27
+        
+        mtspr dbat1u, r26
+        mtspr dbat1l, r27
+        
+        # BAT2
+        
+        sub r31, r31, r29             # r31 = r31 - r29
+        
+        # r29 = min(r31, r30)
+        
+        cmpw r31, r30
+        blt bat2_r31
+        
+                mr r29, r30
+                b bat2_r30
+        
+        bat2_r31:
+        
+                mr r29, r31
+        
+        bat2_r30:
+        
+        BAT_COMPUTE 0x2000 r29 r28 r27 r26
+        mtspr ibat2u, r26
+        mtspr ibat2l, r27
+        
+        mtspr dbat2u, r26
+        mtspr dbat2l, r27
+        
+        # BAT3
+        
+        sub r31, r31, r29             # r31 = r31 - r29
+        
+        # r29 = min(r31, r30)
+        
+        cmpw r31, r30
+        blt bat3_r31
+        
+                mr r29, r30
+                b bat3_r30
+        
+        bat3_r31:
+        
+                mr r29, r31
+        
+        bat3_r30:
+        
+        BAT_COMPUTE 0x3000 r29 r28 r27 r26
+        mtspr ibat3u, r26
+        mtspr ibat3l, r27
+        
+        mtspr dbat3u, r26
+        mtspr dbat3l, r27
         
         no_bat: