Added rough emulation support for div/rem/mul.

config.h.in

@@ -33,5 +33,8 @@
 /* Define if subproject MCPPBS_SPROJ_NORM is enabled */
 #undef SOFTFLOAT_RISCV_ENABLED
 
+/* Define if subproject MCPPBS_SPROJ_NORM is enabled */
+#undef SOFTINT_ENABLED
+
 /* Define to 1 if you have the ANSI C header files. */
 #undef STDC_HEADERS

configure.ac

@@ -83,7 +83,7 @@ AX_DEFAULT_CONFIGURE_ARG([--host=riscv])
 # The '*' suffix indicates an optional subproject. The '**' suffix
 # indicates an optional subproject which is also the name of a group.
 
-MCPPBS_SUBPROJECTS([ pk, softfloat, softfloat_riscv ])
+MCPPBS_SUBPROJECTS([ pk, softfloat, softfloat_riscv, softint ])
 
 #-------------------------------------------------------------------------
 # MCPPBS subproject groups

pk/handlers.c

@@ -4,7 +4,7 @@
 
 int have_fp = 1; // initialized to 1 because it can't be in the .bss section!
 int have_vector = 1;
-
+  
 static void handle_vector_disabled(trapframe_t* tf)
 {
   if (have_vector)
@@ -41,6 +41,12 @@ static void handle_illegal_instruction(trapframe_t* tf)
   }
 #endif
 
+  if(emulate_int(tf) == 0)
+  {
+    advance_pc(tf);
+    return;
+  }
+
   dump_tf(tf);
   panic("An illegal instruction was executed!");
 }

pk/int.c

@@ -0,0 +1,66 @@
+#include "pk.h"
+#include "pcr.h"
+
+
+#include "softint.h"
+#include "riscv-opc.h"
+#include <stdint.h>
+
+#define noisy 0
+
+
+int emulate_int(trapframe_t* tf)
+{
+  if(noisy)
+    printk("Int emulation at pc %lx, insn %x\n",tf->epc,(uint32_t)tf->insn);
+
+  #define RS1 ((tf->insn >> 22) & 0x1F)
+  #define RS2 ((tf->insn >> 17) & 0x1F)
+  #define RD  ((tf->insn >> 27) & 0x1F)
+
+//  #define XRS1 (tf->gpr[RS1])
+//  #define XRS2 (tf->gpr[RS2])
+  #define XRD  (tf->gpr[RD])
+
+  unsigned long xrs1 = tf->gpr[RS1];
+  unsigned long xrs2 = tf->gpr[RS2];
+
+  #define IS_INSN(x) ((tf->insn & MASK_ ## x) == MATCH_ ## x)
+   
+  if(IS_INSN(DIV))
+  {
+    if(noisy)
+      printk("emulating div\n");
+    XRD = softint_divu(xrs1, xrs2);
+  }
+  else if(IS_INSN(DIVU))
+  {
+    if(noisy)
+      printk("emulating divu\n");
+    XRD = softint_divu( xrs1, xrs2);
+  }
+  else if(IS_INSN(MUL))
+  {
+    if(noisy)
+      printk("emulating mul\n");
+    XRD = softint_mul(xrs1, xrs2);
+  }
+  else if(IS_INSN(REM))
+  {
+    if(noisy)
+      printk("emulating rem\n");
+    XRD = softint_remu(xrs1, xrs2);
+  }
+  else if(IS_INSN(REMU))
+  {
+    if(noisy)
+      printk("emulating remu\n");
+    XRD = softint_remu(xrs1, xrs2);
+  }
+  else
+    return -1;
+
+  return 0;
+}
+
+

pk/pk.h

@@ -32,6 +32,8 @@ extern uint32_t mem_mb;
 int emulate_fp(trapframe_t*);
 void init_fp(trapframe_t* tf);
 
+int emulate_int(trapframe_t*);
+
 void printk(const char* s, ...);
 void init_tf(trapframe_t*, long pc, long sp, int user64);
 void pop_tf(trapframe_t*);

pk/pk.mk.in

@@ -1,6 +1,7 @@
 pk_subproject_deps = \
 	softfloat_riscv \
 	softfloat \
+	softint \
 
 pk_hdrs = \
 	pk.h \
@@ -19,6 +20,7 @@ pk_c_srcs = \
 	handlers.c \
 	frontend.c \
 	fp.c \
+	int.c \
 	memset.c \
 	strlen.c \
 	elf.c \

softint/divu.c

@@ -0,0 +1,45 @@
+
+#include <stdint.h>
+
+long 
+ softint_divu( long rs1, long rs2 )
+{
+  // only designed to work for mabi=32
+  // quotient = dividend / divisor + remainder
+  unsigned long long dividend = rs1;
+  unsigned long long divisor  = rs2;
+
+
+  if (divisor == 0) return -1; 
+
+  unsigned long long temp_dividend = dividend;
+  unsigned long long temp_divisor = divisor;
+
+  unsigned long long quotient = 0;
+
+
+  for (int i=0; i <= 32; i++)
+  {
+    unsigned long long temp_quotient = 1;
+     
+    if (temp_divisor == temp_dividend)  { quotient += 1; break;}
+    else if (temp_dividend < temp_divisor) { quotient += 0; break; }
+
+    while (temp_divisor <= temp_dividend && temp_quotient != 0)
+    {
+      temp_divisor = temp_divisor << 1;
+      temp_quotient = temp_quotient << 1;
+    }
+
+    temp_divisor = temp_divisor >> 1;
+    temp_quotient = temp_quotient >> 1;
+
+      
+    temp_dividend = temp_dividend - temp_divisor;
+    temp_divisor = divisor;
+    quotient += temp_quotient;
+  }
+
+  return (long) quotient;
+}
+

softint/mul.c

@@ -0,0 +1,22 @@
+ 
+#include <stdint.h>
+
+long softint_mul( long x, long y )
+{
+
+  int i;
+  long result = 0;
+
+  for (i = 0; i < sizeof(long); i++) {
+    if ((x & 0x1) == 1)
+      result = result + y;
+
+    x = x >> 1;
+    y = y << 1;
+  }
+
+  return result;
+
+}
+
+ 

softint/remu.c

@@ -0,0 +1,38 @@
+
+#include <stdint.h>
+
+long 
+ softint_remu( long rs1, long rs2 )
+{
+  // only designed to work for mabi=32
+  // quotient = dividend / divisor + remainder
+
+  unsigned long long dividend = rs1;
+  unsigned long long divisor  = rs2;
+
+  if (divisor == 0) { return dividend; }
+
+  long long temp_dividend = dividend;
+  long long temp_divisor = divisor;
+
+  for (int i=0; i <= 32; i++)
+  {
+    if (temp_divisor == temp_dividend) { return 0; }
+    else if (temp_dividend < temp_divisor) { return (long) temp_dividend; }
+
+
+    while (temp_divisor <= temp_dividend && temp_divisor != 0)
+    {
+      temp_divisor = temp_divisor << 1;
+    }
+
+    temp_divisor = temp_divisor >> 1;
+
+
+    temp_dividend = temp_dividend - temp_divisor;
+    temp_divisor = divisor;
+  }
+
+  return (long) temp_dividend;
+}
+

softint/softint.ac

@@ -0,0 +1 @@
+

softint/softint.h

@@ -0,0 +1,23 @@
+
+#ifndef softint_h
+#define softint_h
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
+/*----------------------------------------------------------------------------
+| Integer Operations.
+*----------------------------------------------------------------------------*/
+
+long softint_divu( long, long );
+long softint_remu( long, long );
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+

softint/softint.mk.in

@@ -0,0 +1,13 @@
+softint_subproject_deps = 
+
+softint_hdrs = \
+	softint.h \
+
+softint_c_srcs = \
+	divu.c                     \
+	mul.c							 	\
+	remu.c                     \
+
+softint_test_srcs =
+
+softint_install_prog_srcs =