From 968408423f8d45deaa12a5c0cf9fc729f2efe38a Mon Sep 17 00:00:00 2001
From: Tim Newsome <tim@sifive.com>
Date: Mon, 23 May 2016 16:17:28 -0700
Subject: [PATCH] Change DCSR bits to match spec.

Cleaned up debug ROM code a little.
---
 debug_rom/debug_rom.S | 30 +++++++++++-------------------
 debug_rom/debug_rom.h |  6 +++---
 riscv/encoding.h      | 28 ++++++++++++++--------------
 3 files changed, 28 insertions(+), 36 deletions(-)

diff --git a/debug_rom/debug_rom.S b/debug_rom/debug_rom.S
index c164eeb..0d97270 100755
--- a/debug_rom/debug_rom.S
+++ b/debug_rom/debug_rom.S
@@ -5,13 +5,6 @@
 
 # TODO: Update these constants once they're finalized in the doc.
 
-#define DCSR                    0x790
-#define DCSR_CAUSE_DEBINT       3
-#define DCSR_HALT_OFFSET        3
-#define DCSR_DEBUGINT_OFFSET    10
-
-#define DSCRATCH                0x792
-
 #define DEBUG_RAM               0x400
 #define DEBUG_RAM_SIZE          64
 
@@ -63,26 +56,25 @@ restore_128:
         sw      s0, (DEBUG_RAM + DEBUG_RAM_SIZE - 4)(zero)
 
 check_halt:
-        csrr    s0, DCSR
-        andi    s0, s0, (1<<DCSR_HALT_OFFSET)
+        csrr    s0, CSR_DCSR
+        andi    s0, s0, DCSR_HALT
         beqz    s0, exit
         j       wait_for_interrupt
 
 exit:
         # Restore s0.
-        csrr    s0, DSCRATCH
-        dret
-
+        csrr    s0, CSR_DSCRATCH
+        .word   0x79200073      # TODO: dret
 
 _entry:
         # Save s0 in DSCRATCH
-        csrw    DSCRATCH, s0
+        csrw    CSR_DSCRATCH, s0
 
         # Check why we're here
-        csrr    s0, DCSR
+        csrr    s0, CSR_DCSR
         # cause is in bits 2:0 of dcsr
-        andi    s0, s0, 7
-        addi    s0, s0, -DCSR_CAUSE_DEBINT
+        andi    s0, s0, DCSR_CAUSE
+        addi    s0, s0, -DCSR_CAUSE_DEBUGINT
         bnez    s0, spontaneous_halt
 
 jdebugram:
@@ -106,11 +98,11 @@ save_128:
 spontaneous_halt:
         csrr    s0, CSR_MHARTID
         sw      s0, SETHALTNOT(zero)
-        csrsi   DCSR, (1<<DCSR_HALT_OFFSET)
+        csrsi   CSR_DCSR, DCSR_HALT
 
 wait_for_interrupt:
-        csrr    s0, DCSR
-        andi    s0, s0, (1<<DCSR_DEBUGINT_OFFSET)
+        csrr    s0, CSR_DCSR
+        andi    s0, s0, DCSR_DEBUGINT
         beqz    s0, wait_for_interrupt
 
         j       jdebugram
diff --git a/debug_rom/debug_rom.h b/debug_rom/debug_rom.h
index c429b22..7463677 100644
--- a/debug_rom/debug_rom.h
+++ b/debug_rom/debug_rom.h
@@ -7,13 +7,13 @@ static const unsigned char debug_rom_raw[] = {
   0x6f, 0x00, 0xc0, 0x00, 0x13, 0x00, 0x00, 0x00, 0x23, 0x2e, 0x80, 0x42,
   0x73, 0x24, 0x00, 0x79, 0x13, 0x74, 0x84, 0x00, 0x63, 0x04, 0x04, 0x00,
   0x6f, 0x00, 0x80, 0x05, 0x73, 0x24, 0x20, 0x79, 0x73, 0x00, 0x20, 0x79,
-  0x73, 0x10, 0x24, 0x79, 0x73, 0x24, 0x00, 0x79, 0x13, 0x74, 0x74, 0x00,
-  0x13, 0x04, 0xd4, 0xff, 0x63, 0x18, 0x04, 0x02, 0x0f, 0x10, 0x00, 0x00,
+  0x73, 0x10, 0x24, 0x79, 0x73, 0x24, 0x00, 0x79, 0x13, 0x74, 0x04, 0x1c,
+  0x13, 0x04, 0x04, 0xf4, 0x63, 0x18, 0x04, 0x02, 0x0f, 0x10, 0x00, 0x00,
   0x73, 0x24, 0x00, 0xf1, 0x63, 0x46, 0x04, 0x00, 0x23, 0x2e, 0x90, 0x42,
   0x67, 0x00, 0x00, 0x40, 0x13, 0x14, 0x14, 0x00, 0x63, 0x46, 0x04, 0x00,
   0x23, 0x3c, 0x90, 0x42, 0x67, 0x00, 0x00, 0x40, 0x13, 0x00, 0x00, 0x00,
   0x67, 0x00, 0x00, 0x40, 0x73, 0x24, 0x40, 0xf1, 0x23, 0x20, 0x80, 0x10,
-  0x73, 0x60, 0x04, 0x79, 0x73, 0x24, 0x00, 0x79, 0x13, 0x74, 0x04, 0x40,
+  0x73, 0x60, 0x04, 0x79, 0x73, 0x24, 0x00, 0x79, 0x13, 0x74, 0x04, 0x02,
   0xe3, 0x0c, 0x04, 0xfe, 0x6f, 0xf0, 0xdf, 0xfb
 };
 static const unsigned int debug_rom_raw_len = 188;
diff --git a/riscv/encoding.h b/riscv/encoding.h
index e3371af..0f1926a 100644
--- a/riscv/encoding.h
+++ b/riscv/encoding.h
@@ -33,21 +33,21 @@
 #define SSTATUS32_SD        0x80000000
 #define SSTATUS64_SD        0x8000000000000000
 
-#define DCSR_XDEBUGVER      (3<<29)
-#define DCSR_HWBPCOUNT      (0xfff<<17)
-#define DCSR_PRV            (3<<14)
-#define DCSR_NDRESET        (1<<13)
-#define DCSR_FULLRESET      (1<<12)
-#define DCSR_STEP           (1<<11)
-#define DCSR_DEBUGINT       (1<<10)
-#define DCSR_STOPCYCLE      (1<<9)
-#define DCSR_STOPTIME       (1<<8)
-#define DCSR_EBREAKM        (1<<7)
-#define DCSR_EBREAKH        (1<<6)
-#define DCSR_EBREAKS        (1<<5)
-#define DCSR_EBREAKU        (1<<4)
+#define DCSR_XDEBUGVER      (3<<30)
+#define DCSR_NDRESET        (1<<29)
+#define DCSR_FULLRESET      (1<<28)
+#define DCSR_HWBPCOUNT      (0xfff<<16)
+#define DCSR_EBREAKM        (1<<15)
+#define DCSR_EBREAKH        (1<<14)
+#define DCSR_EBREAKS        (1<<13)
+#define DCSR_EBREAKU        (1<<12)
+#define DCSR_STOPCYCLE      (1<<10)
+#define DCSR_STOPTIME       (1<<9)
+#define DCSR_CAUSE          (7<<6)
+#define DCSR_DEBUGINT       (1<<5)
 #define DCSR_HALT           (1<<3)
-#define DCSR_CAUSE          7
+#define DCSR_STEP           (1<<2)
+#define DCSR_PRV            (3<<0)
 
 #define DCSR_CAUSE_NONE     0
 #define DCSR_CAUSE_SWBP     1
-- 
2.30.2