[xcc,pk,sim] Added first part of FP support

In particular, FP loads, stores, and moves now work.

8 files changed, 1024 insertions, 27 deletions

diff --git a/Makefile b/Makefile
index b73bf20..6a1accd 100644
--- a/Makefile
+++ b/Makefile
@@ -5,8 +5,8 @@ TARGETS := pk
 
 all: $(TARGETS)
 
-pk: boot.o entry.o pk.o syscall.o file.o frontend.o pk.ld
-	$(CC) -o pk entry.o pk.o syscall.o file.o frontend.o -T pk.ld
+pk: boot.o entry.o pk.o syscall.o file.o frontend.o handlers.o pk.ld
+	$(CC) -o pk entry.o pk.o syscall.o file.o frontend.o handlers.o -T pk.ld
 
 %.o: %.c *.h
 	$(CC) -c $<
diff --git a/boot.S b/boot.S
index c74327a..4318a40 100644
--- a/boot.S
+++ b/boot.S
@@ -1,10 +1,12 @@
+#include "pcr.h"
+
 	.text
 	.global __start
 	.ent    __start
 __start:
 
 	# set up SR
-	li		$t0, 0xFF
+	li		$t0, SR_S | SR_PS | SR_ET | SR_UX | SR_KX
 	mtpcr	$t0, $0
 
 	# set up trap table
diff --git a/entry.S b/entry.S
index ae76962..db49a98 100644
--- a/entry.S
+++ b/entry.S
@@ -1,5 +1,6 @@
 	.text
-	.set noat
+	.set	noat
+	.ent	save_tf
 save_tf:	# write the trap frame onto the stack
 	# save gprs
 	sd		$1,8($k1)
@@ -39,11 +40,15 @@ save_tf:	# write the trap frame onto the stack
 	mfpcr	$t0,$2			# badvaddr
 	sd		$t0,272($k1)
 	jr		$ra
+	.end	save_tf
 
-	.global pop_tf
+	.globl	pop_tf
+	.ent	pop_tf
 pop_tf:	# write the trap frame onto the stack
 	# restore gprs
-	di
+	ld		$t0,256($a0)	# restore sr, which should disable interrupts
+	mtpcr	$t0,$0
+
 	move	$k0,$a0
 	ld		$1,8($k0)
 	ld		$2,16($k0)
@@ -79,6 +84,7 @@ pop_tf:	# write the trap frame onto the stack
 	ld		$k0,264($k0)
 	mtpcr	$k0,$1
 	eret
+	.end	pop_tf
 
 
 
@@ -95,16 +101,26 @@ pop_tf:	# write the trap frame onto the stack
 
 	.align	12
 	.global	trap_table
+	.ent	trap_table
 trap_table:
-	TRAP_TABLE_ENTRY(unhandled_trap)
-	TRAP_TABLE_ENTRY(unhandled_trap)
-	TRAP_TABLE_ENTRY(unhandled_trap)
-	TRAP_TABLE_ENTRY(unhandled_trap)
-	TRAP_TABLE_ENTRY(unhandled_trap)
-	TRAP_TABLE_ENTRY(unhandled_trap)
+	TRAP_TABLE_ENTRY(handle_illegal_instruction)
+	TRAP_TABLE_ENTRY(handle_privileged_instruction)
+	TRAP_TABLE_ENTRY(handle_fp_disabled)
+	TRAP_TABLE_ENTRY(handle_badtrap)
+	TRAP_TABLE_ENTRY(handle_misaligned_fetch)
+	TRAP_TABLE_ENTRY(handle_misaligned_ldst)
+	TRAP_TABLE_ENTRY(handle_fault_fetch)
+	TRAP_TABLE_ENTRY(handle_fault_ldst)
 	TRAP_TABLE_ENTRY(handle_syscall)
 	TRAP_TABLE_ENTRY(handle_breakpoint)
-	.align 12
+	TRAP_TABLE_ENTRY(handle_badtrap)
+	TRAP_TABLE_ENTRY(handle_badtrap)
+	TRAP_TABLE_ENTRY(handle_badtrap)
+	TRAP_TABLE_ENTRY(handle_badtrap)
+	TRAP_TABLE_ENTRY(handle_badtrap)
+	TRAP_TABLE_ENTRY(handle_badtrap)
+	.align	12
+	.end	trap_table
 
 	.bss
 	.global stack_bot
diff --git a/handlers.c b/handlers.c
new file mode 100644
index 0000000..6cc5958
--- /dev/null
+++ b/handlers.c
@@ -0,0 +1,58 @@
+#include "pcr.h"
+#include "pk.h"
+
+void handle_breakpoint(trapframe_t* tf)
+{
+  printk("Breakpoint\n");
+  dump_tf(tf);
+  tf->epc += 4;
+  pop_tf(tf);
+}
+
+void handle_fp_disabled(trapframe_t* tf)
+{
+  tf->sr |= SR_EF;
+  pop_tf(tf);
+}
+
+void handle_badtrap(trapframe_t* tf)
+{
+  dump_tf(tf);
+  panic("Bad trap vector!");
+}
+
+void handle_privileged_instruction(trapframe_t* tf)
+{
+  dump_tf(tf);
+  panic("A privileged instruction was executed!");
+}
+
+void handle_illegal_instruction(trapframe_t* tf)
+{
+  dump_tf(tf);
+  panic("An illegal instruction was executed!");
+}
+
+void handle_misaligned_fetch(trapframe_t* tf)
+{
+  dump_tf(tf);
+  panic("Misaligned instruction access!");
+}
+
+void handle_misaligned_ldst(trapframe_t* tf)
+{
+  dump_tf(tf);
+  panic("Misaligned data access!");
+}
+
+void handle_fault_fetch(trapframe_t* tf)
+{
+  dump_tf(tf);
+  panic("Faulting instruction access!");
+}
+
+void handle_fault_ldst(trapframe_t* tf)
+{
+  dump_tf(tf);
+  panic("Faulting data access!");
+}
diff --git a/mcf.out b/mcf.out
new file mode 100644
index 0000000..959caba
--- /dev/null
+++ b/mcf.out
@@ -0,0 +1,915 @@
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diff --git a/pcr.h b/pcr.h
index 22650a3..23e6185 100644
--- a/pcr.h
+++ b/pcr.h
@@ -1,6 +1,16 @@
 #ifndef _RISCV_COP0_H
 #define _RISCV_COP0_H
 
+#define SR_ET    0x0000000000000001
+#define SR_PS    0x0000000000000004
+#define SR_S     0x0000000000000008
+#define SR_EF    0x0000000000000010
+#define SR_UX    0x0000000000000020
+#define SR_KX    0x0000000000000040
+#define SR_IM    0x000000000000FF00
+
+#ifndef __ASSEMBLER__
+
 #define mtpcr(val,reg) ({ long __tmp = (long)(val); \
                           asm volatile ("mtpcr %0,$%1"::"r"(__tmp),"i"(reg)); })
 
@@ -9,3 +19,5 @@
                       __tmp; })
 
 #endif
+
+#endif
diff --git a/pk.c b/pk.c
index bfc4dad..2f0ba17 100644
--- a/pk.c
+++ b/pk.c
@@ -1,3 +1,4 @@
+#include "pcr.h"
 #include "pk.h"
 #include "file.h"
 #include "frontend.h"
@@ -119,18 +120,12 @@ void dump_tf(trapframe_t* tf)
   printk("sr %lx pc %lx va %lx\n",tf->sr,tf->epc,tf->badvaddr);
 }
 
-void unhandled_trap(trapframe_t* tf)
+void init_tf(trapframe_t* tf, long pc, long sp)
 {
-  dump_tf(tf);
-  panic("unhandled trap!");
-}
-
-void handle_breakpoint(trapframe_t* tf)
-{
-  printk("Breakpoint\n");
-  dump_tf(tf);
-  tf->epc += 4;
-  pop_tf(tf);
+  memset(tf,0,sizeof(*tf));
+  tf->sr = SR_S | SR_KX | SR_UX; // SR_PS=0 (usermode); SR_ET=0
+  tf->gpr[29] = USER_MEM_SIZE-USER_MAINVARS_SIZE;
+  tf->epc = USER_START;
 }
 
 void bss_init()
@@ -150,9 +145,7 @@ void mainvars_init()
 void jump_usrstart()
 {
   trapframe_t tf;
-  memset(&tf,0,sizeof(tf));
-  tf.gpr[29] = USER_MEM_SIZE-USER_MAINVARS_SIZE;
-  tf.epc = USER_START;
+  init_tf(&tf, USER_START, USER_MEM_SIZE-USER_MAINVARS_SIZE);
   pop_tf(&tf);
 }
 
diff --git a/pk.h b/pk.h
index eab43fd..dfe68f7 100644
--- a/pk.h
+++ b/pk.h
@@ -21,6 +21,7 @@ extern "C" {
 #endif
 
 void printk(const char* s, ...);
+void init_tf(trapframe_t*, long pc, long sp);
 void pop_tf(trapframe_t*);
 void dump_tf(trapframe_t*);