Update machine.adockersten1-patch-3

Updated description based on info from comments

Signed-off-by: Kersten Richter <kersten@riscv.org>

1 files changed, 8 insertions, 9 deletions

diff --git a/src/machine.adoc b/src/machine.adoc
index 6febd8c..5cfec0c 100644
--- a/src/machine.adoc
+++ b/src/machine.adoc
@@ -2509,15 +2509,14 @@ available only to machine-mode.
 ==== Main Memory versus I/O versus Vacant Regions
 
 The most important characterization of a specific memory address range is
-whether it holds regular main memory, I/O devices, or if it is vacant.
-Regular main memory is required to have a number of properties,
-which are specified in the following sections. However, I/O device regions can have a much broader  
-range of attributes. Address regions that do not fit into regular main memory are categorized as 
-I/O; for example, regions that contain device control registers. Finally, there are 
-other address regions that are neither memory nor I/O that are called vacant
-regions. Vacant regions include attributes that specify access to these regions isn't 
-supported. Vacant regions can also be classified as I/O regions, but include attributes that specify that access is not supported. Any 
-attempt to access a vacant region causes an access-fault exception.
+whether it holds regular main memory or I/O devices, or if it is vacant.
+Regular main memory is required to have a number of properties, which are 
+outlined in the following sections. Address regions that do not fit into regular 
+main memory are categorized as I/O; for example, regions that contain device 
+control registers. I/O regions have a much broader range of attributes. 
+Vacant regions are classified as I/O regions. However, they include attributes that 
+specify that access to these regions is not supported. Any attempt to access a 
+vacant region causes an access-fault exception.
 
 ==== Supported Access Type PMAs