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diff --git a/src/threads/io.h b/src/threads/io.h
index ed9f55f13b2630ff3233bd7167f13874e540c464..39a135dcc23e46abfa21551a1b8f1c13753a9cf5 100644 (file)
--- a/src/threads/io.h
+++ b/src/threads/io.h
@@ -4,6 +4,7 @@
 #include <stddef.h>
 #include <stdint.h>
 
+/* Reads and returns a byte from PORT. */
 static inline uint8_t
 inb (uint16_t port)
 {
@@ -12,6 +13,8 @@ inb (uint16_t port)
   return data;
 }
 
+/* Reads CNT bytes from PORT, one after another, and stores them
+   into the buffer starting at ADDR. */
 static inline void
 insb (uint16_t port, void *addr, size_t cnt)
 {
@@ -21,6 +24,7 @@ insb (uint16_t port, void *addr, size_t cnt)
                 : "memory", "cc");
 }
 
+/* Reads and returns 16 bits from PORT. */
 static inline uint16_t
 inw (uint16_t port)
 {
@@ -29,6 +33,8 @@ inw (uint16_t port)
   return data;
 }
 
+/* Reads CNT 16-bit (halfword) units from PORT, one after
+   another, and stores them into the buffer starting at ADDR. */
 static inline void
 insw (uint16_t port, void *addr, size_t cnt)
 {
@@ -38,6 +44,7 @@ insw (uint16_t port, void *addr, size_t cnt)
                 : "memory", "cc");
 }
 
+/* Reads and returns 32 bits from PORT. */
 static inline uint32_t
 inl (uint16_t port)
 {
@@ -46,8 +53,10 @@ inl (uint16_t port)
   return data;
 }
 
+/* Reads CNT 32-bit (word) units from PORT, one after another,
+   and stores them into the buffer starting at ADDR. */
 static inline void
-insl(uint16_t port, void *addr, size_t cnt)
+insl (uint16_t port, void *addr, size_t cnt)
 {
   asm volatile ("cld; repne; insl"
                 : "=D" (addr), "=c" (cnt)
@@ -55,12 +64,15 @@ insl(uint16_t port, void *addr, size_t cnt)
                 : "memory", "cc");
 }
 
+/* Writes byte DATA to PORT. */
 static inline void
-outb(uint16_t port, uint8_t data)
+outb (uint16_t port, uint8_t data)
 {
   asm volatile ("outb %0,%w1" : : "a" (data), "d" (port));
 }
 
+/* Writes to PORT each byte of data in the CNT-byte buffer
+   starting at ADDR. */
 static inline void
 outsb (uint16_t port, const void *addr, size_t cnt)
 {
@@ -70,12 +82,15 @@ outsb (uint16_t port, const void *addr, size_t cnt)
                 : "cc");
 }
 
+/* Writes the 16-bit DATA to PORT. */
 static inline void
 outw (uint16_t port, uint16_t data)
 {
   asm volatile ("outw %0,%w1" : : "a" (data), "d" (port));
 }
 
+/* Writes to PORT each 16-bit unit (halfword) of data in the
+   CNT-halfword buffer starting at ADDR. */
 static inline void
 outsw (uint16_t port, const void *addr, size_t cnt)
 {
@@ -85,10 +100,22 @@ outsw (uint16_t port, const void *addr, size_t cnt)
                 : "cc");
 }
 
+/* Writes the 32-bit DATA to PORT. */
 static inline void
 outl (uint16_t port, uint32_t data)
 {
   asm volatile ("outl %0,%w1" : : "a" (data), "d" (port));
 }
 
+/* Writes to PORT each 32-bit unit (word) of data in the CNT-word
+   buffer starting at ADDR. */
+static inline void
+outsl (uint16_t port, const void *addr, size_t cnt)
+{
+  asm volatile ("cld; repne; outsl"
+                : "=S" (addr), "=c" (cnt)
+                : "d" (port), "0" (addr), "1" (cnt)
+                : "cc");
+}
+
 #endif /* io.h */