fix a few comments in exec.c

diff -X excl -rduNp qemu.oorig/exec.c qemu/exec.c
@@ -2167,7 +2167,7 @@ void stl_phys(target_phys_addr_t addr, u
 }
 
 #else
-void cpu_physical_memory_rw(target_phys_addr_t addr, uint8_t *buf, 
+void cpu_physical_memory_rw(target_phys_addr_t addr, uint8_t *buf,
                             int len, int is_write)
 {
     int l, io_index;

@@ -2176,7 +2176,7 @@ void cpu_physical_memory_rw(target_phys_
     target_phys_addr_t page;
     unsigned long pd;
     PhysPageDesc *p;
-    
+
     while (len > 0) {
         page = addr & TARGET_PAGE_MASK;
         l = (page + TARGET_PAGE_SIZE) - addr;

@@ -2188,22 +2188,22 @@ void cpu_physical_memory_rw(target_phys_
         } else {
             pd = p->phys_offset;
         }
-        
+
         if (is_write) {
             if ((pd & ~TARGET_PAGE_MASK) != IO_MEM_RAM) {
                 io_index = (pd >> IO_MEM_SHIFT) & (IO_MEM_NB_ENTRIES - 1);
                 if (l >= 4 && ((addr & 3) == 0)) {
-                    /* 32 bit read access */
+                    /* 32 bit write access */
                     val = ldl_p(buf);
                     io_mem_write[io_index][2](io_mem_opaque[io_index], addr, val);
                     l = 4;
                 } else if (l >= 2 && ((addr & 1) == 0)) {
-                    /* 16 bit read access */
+                    /* 16 bit write access */
                     val = lduw_p(buf);
                     io_mem_write[io_index][1](io_mem_opaque[io_index], addr, val);
                     l = 2;
                 } else {
-                    /* 8 bit access */
+                    /* 8 bit write access */
                     val = ldub_p(buf);
                     io_mem_write[io_index][0](io_mem_opaque[io_index], addr, val);
                     l = 1;

@@ -2218,7 +2218,7 @@ void cpu_physical_memory_rw(target_phys_
                     /* invalidate code */
                     tb_invalidate_phys_page_range(addr1, addr1 + l, 0);
                     /* set dirty bit */
-                    phys_ram_dirty[addr1 >> TARGET_PAGE_BITS] |= 
+                    phys_ram_dirty[addr1 >> TARGET_PAGE_BITS] |=
                         (0xff & ~CODE_DIRTY_FLAG);
                 }
             }

@@ -2237,14 +2237,14 @@ void cpu_physical_memory_rw(target_phys_
                     stw_p(buf, val);
                     l = 2;
                 } else {
-                    /* 8 bit access */
+                    /* 8 bit read access */
                     val = io_mem_read[io_index][0](io_mem_opaque[io_index], addr);
                     stb_p(buf, val);
                     l = 1;
                 }
             } else {
                 /* RAM case */
-                ptr = phys_ram_base + (pd & TARGET_PAGE_MASK) + 
+                ptr = phys_ram_base + (pd & TARGET_PAGE_MASK) +
                     (addr & ~TARGET_PAGE_MASK);
                 memcpy(buf, ptr, l);
             }