From f66559eed5f91d9b83bf12a5bdc5f4c8deab390e Mon Sep 17 00:00:00 2001 From: Lynn Stricklan Date: Mon, 4 Jan 2021 20:16:15 -0700 Subject: [PATCH] Update msbin.c The processing for MKDMBF$ fails for numbers smaller than 1. Basic cause is the check for exponent overflow is incorrect. Changed code to correctly check for exponent overflow --- internal/c/msbin.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/internal/c/msbin.c b/internal/c/msbin.c index 85890be91..f623b7ab4 100644 --- a/internal/c/msbin.c +++ b/internal/c/msbin.c @@ -214,7 +214,7 @@ int32 _dieeetomsbin(double *src8, double *dest8) /* Make a clobberable copy of the source number */ memcpy(ieee,src8,8); //strncpy((char *)ieee,(char *)src8,8); - for (i=0; i<8; i++) msbin[i] = 0; + memset(msbin, 0, sizeof(*dest8)); //for (i=0; i<8; i++) msbin[i] = 0; /* If all are zero in src8, the msbin should be zero */ for (i=0; i<8; i++) any_on |= ieee[i]; @@ -222,12 +222,15 @@ int32 _dieeetomsbin(double *src8, double *dest8) sign = ieee[7] & 0x80; msbin[6] |= sign; - msbin_exp = (unsigned)(ieee[7] & 0x7f) * 0x10; + msbin_exp = (unsigned)(ieee[7] & 0x7f) << 4; //(unsigned)(ieee[7] & 0x7f) * 0x10; msbin_exp += ieee[6] >> 4; - if (msbin_exp-0x3ff > 0x80) return 1; - - msbin[7] = msbin_exp - 0x3ff + 0x80 + 1; + // verify the exponent is in range for MBF encoding + msbin_exp = msbin_exp - 0x3ff + 0x80 + 1; + if ((msbin_exp & 0xff00) != 0) return 1; + msbin[7] = msbin_exp; + // if (msbin_exp-0x3ff > 0x80) return 1; + // msbin[7] = msbin_exp - 0x3ff + 0x80 + 1; /* The ieee mantissa must be shifted up 3 bits */ ieee[6] &= 0x0f; /* mask out the exponent in the second byte */