Renamed csr.[ch] to clint.[ch], moved some code around and did some c…

…leanup, no logic change

csr.c → clint.c

@@ -1,43 +1,18 @@
-// csr.c: CSR-related handling
+// clint.c: CLINT, UART emulation
 #include <stdint.h>
 #include <windows.h>
 #include <conio.h>
 #include <stdio.h>
 
-#include "csr.h"
+#include "clint.h"
 
-#define NO_CSRS 4096
 
-// explicit init function?
-static uint32_t CSRs[NO_CSRS];
-
-// visible through memory I/O
+// CLINT I/O registers
 static uint32_t timer_l = 0;	// part of CLINT, mtime in SiFive doc
 static uint32_t timer_h = 0;
 static uint32_t timer_match_l = 0;	// part of CLINT, mtimecmp in SiFive doc
 static uint32_t timer_match_h = 0;	
 
-extern uint32_t no_readkbhit;
-
-uint32_t read_CSR(uint32_t CSR_no)
-{
-	if (CSR_no == CSR_MISA)
-		return 0x40401101;
-	else if (CSR_no == CSR_MVENDORID)
-		return 0xff0fff0f;
-	else if (CSR_no == CSR_CYCLE)
-		return no_cycles;
-	else if (CSR_no & 0xc00) {
-		//printf("read_CSR: 0x%x\n", CSR_no);
-	}
-		return CSRs[CSR_no];
-}
-
-uint32_t write_CSR(uint32_t CSR_no, uint32_t value)
-{
-	CSRs[CSR_no] = value;
-	return 1;
-}
 
 uint32_t io_read(uint32_t addr, uint32_t *data)
 {
@@ -131,15 +106,15 @@ if (is_escape_sequence)
 // increment timer and also see if we've exceeded threshold
 uint32_t run_clint()
 {
-	uint32_t interrupt = 0;
+	uint32_t gen_interrupt = 0;
 
 	static uint64_t last_time = 0;
 	uint64_t elapsed_time = 0;
 
 	if (last_time == 0) {
 		// initialize last_time
 		last_time = get_microseconds();
-		return interrupt;
+		return gen_interrupt;
 	} else {
 		// calculate current time and update timer
 		elapsed_time = get_microseconds() - last_time;
@@ -167,8 +142,8 @@ uint32_t run_clint()
 	// generate interrupt only if it's enabled
 	// MIP.MTIP , MIE.MTIE , MSTATUS.MIE
 	if ((mip&0x80) && (mie&0x80) && (mstatus & 0x8)) {
-		interrupt = 0x80000007;
+		gen_interrupt = 0x80000007;
 	}
-	return interrupt;
+	return gen_interrupt;
 }
 

csr.h → clint.h

@@ -30,9 +30,6 @@
 
 extern uint32_t no_cycles, wfi;
 
-uint32_t read_CSR(uint32_t CSR_no);
-uint32_t write_CSR(uint32_t CSR_no, uint32_t value);
-
 uint32_t io_read(uint32_t addr, uint32_t* data);
 uint32_t io_write(uint32_t addr, uint32_t* data);
 

rv-emulator.c

@@ -3,7 +3,7 @@
 #include <assert.h>
 #include <stdlib.h> //for exit()
 
-#include "csr.h"
+#include "clint.h"
 
 
 // initial instruction address upon startup
@@ -145,10 +145,11 @@ static uint8_t mem[MEMSIZE];   // main memory
 #define MEMIO_START 0x10000000
 #define MEMIO_END 0x12000000    // exclusive
 
-
+#define NO_CSRS 4096
 
 // CPU internal state
 static REGISTER regs[32];
+static uint32_t CSRs[NO_CSRS];  // explicit init?
 static unsigned int pc ;       // 32-bit PC
 static unsigned int mode;      // privilege mode: currently M only
 static unsigned int reservation;   // address for lr/sc ; top 29 bits
@@ -160,8 +161,6 @@ static unsigned int trace = 0;  // trace every instruction
 static unsigned int interrupt;  // interrupt type
 static uint32_t dtb_offset;    // offset to DTB
 
-uint32_t no_readkbhit = 0;
-
 // read register
 // can optimize by always 0 in x0
 REGISTER read_reg(int reg_no)
@@ -178,6 +177,29 @@ int write_reg(int reg_no, REGISTER data)
 }
 
 
+uint32_t read_CSR(uint32_t CSR_no)
+{
+    if (CSR_no == CSR_MISA)
+        return 0x40401101;
+    else if (CSR_no == CSR_MVENDORID)
+        return 0xff0fff0f;
+    else if (CSR_no == CSR_CYCLE)
+        return no_cycles;
+    else if (CSR_no & 0xc00) {
+        //printf("read_CSR: 0x%x\n", CSR_no);
+    }
+    return CSRs[CSR_no];
+}
+
+uint32_t write_CSR(uint32_t CSR_no, uint32_t value)
+{
+    CSRs[CSR_no] = value;
+    return 1;
+}
+
+
+
+
 // memory operation, no sign extension done here
 // memory address start at INITIAL_PC, no memory storage below that address
 // can improve perf by handling multiple bytes at once
@@ -620,10 +642,6 @@ int execute_code()
         interrupt = 0;
         no_cycles++;
 
-        if ((no_cycles % 10000) == 0) {
-            // printf("cycle #: %d , pc=0x%x , kbhit=%d\n", no_cycles, pc , no_readkbhit);
-        }
-
         // run clint every 1024 instructions
         if ((no_cycles & 0x3ff) == 0) {
             interrupt = run_clint();
@@ -765,21 +783,20 @@ void debug_syscall() {
 }
 
 
-// takes one optional argument: machine code file name
+// takes two optional argument: machine code file name & dtb file name
 int main(int argc, char** argv)
 {
     load_code((argc<=1)?DEFAULT_FILE:argv[1]);
     if (argc >= 2) load_dtb(argv[2]) ;
 
+    // initialize CPU state
     pc = INITIAL_PC;
     mode = MODE_M; // Machine-mode.
     no_cycles = 0;
 
     // a10 and a11 needed for Linux
     write_reg(10, 0x0); // hart ID
     write_reg(11, dtb_offset + INITIAL_PC); // DTB address in memory
-
-    // system("");
-
+
     execute_code();
 }

rvsim.vcxproj

@@ -119,7 +119,7 @@
     </Link>
   </ItemDefinitionGroup>
   <ItemGroup>
-    <ClCompile Include="csr.c" />
+    <ClCompile Include="clint.c" />
     <ClCompile Include="rv-emulator.c" />
   </ItemGroup>
   <ItemGroup>
@@ -129,7 +129,7 @@
     <Text Include="tasks.txt" />
   </ItemGroup>
   <ItemGroup>
-    <ClInclude Include="csr.h" />
+    <ClInclude Include="clint.h" />
   </ItemGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">

rvsim.vcxproj.filters

@@ -18,7 +18,7 @@
     <ClCompile Include="rv-emulator.c">
       <Filter>Source Files</Filter>
     </ClCompile>
-    <ClCompile Include="csr.c">
+    <ClCompile Include="clint.c">
       <Filter>Source Files</Filter>
     </ClCompile>
   </ItemGroup>
@@ -29,7 +29,7 @@
     <Text Include="tasks.txt" />
   </ItemGroup>
   <ItemGroup>
-    <ClInclude Include="csr.h">
+    <ClInclude Include="clint.h">
       <Filter>Header Files</Filter>
     </ClInclude>
   </ItemGroup>