From: kub <derkub@gmail.com>
Date: Wed, 20 Nov 2019 00:01:33 +0000 (+0100)
Subject: sh2 drc: fixed some RISC-V bugs
X-Git-Tag: v2.00~811
X-Git-Url: https://notaz.gp2x.de/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f1da0a362f536c8df30a739541e3665024b40544;p=picodrive.git

sh2 drc: fixed some RISC-V bugs
---

diff --git a/README.md b/README.md
index 8154f7dc..67f60c2c 100644
--- a/README.md
+++ b/README.md
@@ -1,14 +1,14 @@
 This is my foray into dynamic recompilation using PicoDrive, a
 Megadrive / Genesis / Sega CD / Mega CD / 32X / SMS emulator.
 
-I added support for MIPS (mips32r1) and ARM64 (aarch64) to the recompiler, as
-well as spent much effort to optimize the code generated by the DRC.
+I added support for MIPS (mips32r1), ARM64 (aarch64) and RISC-V (RV64IM) to the
+SH2 recompiler, as well as spent much effort to optimize the DRC-generated code.
 I also optimized SH2 memory access inside the emulator, and did some work on
 M68K/SH2 CPU synchronization to fix some problems and speed up the emulator.
 
-It got a bit out of hand. I ended up doing fixes and optimzations all over the
+It got a bit out of hand. I ended up doing fixes and optimizations all over the
 place, mainly for 32X and CD, 32X graphics handling, and probably some more,
-see the commit history.
+see the commit history. As a result, 32X emulation speed has improved a lot.
 
 ### compiling
 
diff --git a/cpu/drc/emit_riscv.c b/cpu/drc/emit_riscv.c
index b66d6350..fe4da035 100644
--- a/cpu/drc/emit_riscv.c
+++ b/cpu/drc/emit_riscv.c
@@ -220,9 +220,9 @@ enum { F2_ALT=0x20, F2_MULDIV=0x01 };
 	/*EMIT(R5_ADDW_IMM(s1, s1, 0));*/ \
 	/*EMIT(R5_ADDW_IMM(s2, s2, 0));*/ \
 	EMIT(R5_MUL(dlo, s1, s2)); \
-	EMIT(R5_LSR_IMM(dhi, dlo, 32)); \
+	EMIT(R5_ASR_IMM(dhi, dlo, 32)); \
 	EMIT(R5_LSL_IMM(dlo, dlo, 32)); \
-	EMIT(R5_LSR_IMM(dlo, dlo, 32)); \
+	EMIT(R5_ASR_IMM(dlo, dlo, 32)); \
 } while (0)
 
 #define EMIT_R5_MULLS_REG(dlo, dhi, s1, s2) \
@@ -1322,7 +1322,7 @@ static int emith_cond_check(int cond, int *r, int *s)
 		u32 r_ = _CB(*ptr_,5,15,0), s_ = _CB(*ptr_,5,20,0); \
 		EMIT_PTR(p_, R5_BCOND(f1_, r_, s_, disp_ & 0x00001fff)); \
 	} else { \
-		u32 *p_ = -- ptr_; \
+		u32 *p_ = ptr_; \
 		uintptr_t target_ = (uintptr_t)(target); \
 		EMIT_PTR(p_, R5_MOVT_IMM(AT, target_ + _CB(target_,1,11,12))); \
 		EMIT_PTR(p_, R5_JR(AT, target_));  \