1 files changed, 15 insertions, 6 deletions
diff --git a/src/cpu/registers.h b/src/cpu/registers.h
index edb6b7b..d2f2e74 100644
--- a/src/cpu/registers.h
+++ b/src/cpu/registers.h
@@ -5,13 +5,22 @@
 namespace x86 {
 
 struct cpu_state {
-  /* pusha */
-  uint32_t edi, esi;  // destination index, source index
-  uint32_t ebp, esp;  // base pointer, stack pointer
-  uint32_t ebx, edx, ecx, eax;  // general registers
+  /* registers stored by pusha */
+  // indexes and pointers
+  uint32_t edi;  // destination index: string, memory copying and setting, far pointer addressing with ES
+  uint32_t esi;  // source index: string and memory copying
+  uint32_t ebp;  // stack base pointer
+  const uint32_t esp;  // stack pointer; this register is not used by popa
 
-  uint32_t irq;
-  uint32_t error;
+  // general registers
+  uint32_t ebx;  // base register: base pointer for memory access
+  uint32_t edx;  // data register: I/O ports, arithmetic
+  uint32_t ecx;  // counter register: loop counter, for shifts
+  uint32_t eax;  // accumulator register: I/O ports, arithmetic
+
+  /* pushed by interrupt handler macros */
+  uint32_t irq;    // interrupt number
+  uint32_t error;  // error code
 
   /* stack frame, pushed by cpu */
   uint32_t eip;