From: Toni Wilen <twilen@winuae.net>
Date: Tue, 30 Jun 2015 17:56:19 +0000 (+0300)
Subject: Truncate to 8-bits, bget in some situations can return upper bit(s) set.
X-Git-Tag: 3200~162
X-Git-Url: https://git.unchartedbackwaters.co.uk/w/?a=commitdiff_plain;h=4a700f1019cc29a4ee7ec2eb6b23d8f3267fc5ec;p=francis%2Fwinuae.git

Truncate to 8-bits, bget in some situations can return upper bit(s) set.
---

diff --git a/gencpu.cpp b/gencpu.cpp
index 65ead649..21500c42 100644
--- a/gencpu.cpp
+++ b/gencpu.cpp
@@ -3410,11 +3410,11 @@ static void gen_opcode (unsigned int opcode)
 		printf ("\tuaecptr memp = m68k_areg (regs, srcreg) + (uae_s32)(uae_s16)%s;\n", gen_nextiword (0));
 		genamode (curi, curi->dmode, "dstreg", curi->size, "dst", 2, 0, 0);
 		if (curi->size == sz_word) {
-			printf ("\tuae_u16 val = (%s (memp) << 8) + %s (memp + 2);\n", srcb, srcb);
+			printf ("\tuae_u16 val = ((%s (memp) & 0xff) << 8) + (%s (memp + 2) & 0xff);\n", srcb, srcb);
 			count_read += 2;
 		} else {
-			printf ("\tuae_u32 val = (%s (memp) << 24) + (%s (memp + 2) << 16)\n", srcb, srcb);
-			printf ("              + (%s (memp + 4) << 8) + %s (memp + 6);\n", srcb, srcb);
+			printf ("\tuae_u32 val = ((%s (memp) & 0xff) << 24) + ((%s (memp + 2) & 0xff) << 16)\n", srcb, srcb);
+			printf ("              + ((%s (memp + 4) & 0xff) << 8) + (%s (memp + 6) & 0xff);\n", srcb, srcb);
 			count_read += 4;
 		}
 		fill_prefetch_next ();
@@ -5061,9 +5061,9 @@ bccl_not68020:
 			printf ("\tuae_u16 val;\n");
 			addmmufixup ("srcreg");
 			printf ("\tm68k_areg (regs, srcreg) -= areg_byteinc[srcreg];\n");
-			printf ("\tval = (uae_u16)%s (m68k_areg (regs, srcreg));\n", srcb);
+			printf ("\tval = (uae_u16)(%s (m68k_areg (regs, srcreg)) & 0xff);\n", srcb);
 			printf ("\tm68k_areg (regs, srcreg) -= areg_byteinc[srcreg];\n");
-			printf ("\tval = (val | ((uae_u16)%s (m68k_areg (regs, srcreg)) << 8)) + %s;\n", srcb, gen_nextiword (0));
+			printf ("\tval = (val | ((uae_u16)(%s (m68k_areg (regs, srcreg)) & 0xff) << 8)) + %s;\n", srcb, gen_nextiword (0));
 			addmmufixup ("dstreg");
 			printf ("\tm68k_areg (regs, dstreg) -= areg_byteinc[dstreg];\n");
 			gen_set_fault_pc ();
@@ -5079,7 +5079,7 @@ bccl_not68020:
 			printf ("\tuae_u16 val;\n");
 			addmmufixup ("srcreg");
 			printf ("\tm68k_areg (regs, srcreg) -= areg_byteinc[srcreg];\n");
-			printf ("\tval = (uae_u16)%s (m68k_areg (regs, srcreg));\n", srcb);
+			printf ("\tval = (uae_u16)(%s (m68k_areg (regs, srcreg)) & 0xff);\n", srcb);
 			printf ("\tval = (((val << 4) & 0xf00) | (val & 0xf)) + %s;\n", gen_nextiword (0));
 			addmmufixup ("dstreg");
 			if (cpu_level >= 2) {