Registers; Floating-Point Registers - Hitachi SH7750 Hardware Manual

6.3

Registers

6.3.1

Floating-Point Registers

Figure 6.4 shows the floating-point register configuration. There are thirty-two 32-bit floating-
point registers, referenced by specifying FR0–FR15, DR0/2/4/6/8/10/12/14, FV0/4/8/12, XF0–
XF15, XD0/2/4/6/8/10/12/14, or XMTRX.
1. Floating-point registers, FPRi_BANKj (32 registers)
FPR0_BANK0–FPR15_BANK0
FPR0_BANK1–FPR15_BANK1
2. Single-precision floating-point registers, FRi (16 registers)
When FPSCR.FR = 0, FR0–FR15 indicate FPR0_BANK0–FPR15_BANK0;
when FPSCR.FR = 1, FR0–FR15 indicate FPR0_BANK1–FPR15_BANK1.
3. Double-precision floating-point registers, DRi (8 registers): A DR register comprises two FR
registers
DR0 = {FR0, FR1}, DR2 = {FR2, FR3}, DR4 = {FR4, FR5}, DR6 = {FR6, FR7},
DR8 = {FR8, FR9}, DR10 = {FR10, FR11}, DR12 = {FR12, FR13}, DR14 = {FR14, FR15}
4. Single-precision floating-point vector registers, FVi (4 registers): An FV register comprises
four FR registers
FV0 = {FR0, FR1, FR2, FR3}, FV4 = {FR4, FR5, FR6, FR7},
FV8 = {FR8, FR9, FR10, FR11}, FV12 = {FR12, FR13, FR14, FR15}
5. Single-precision floating-point extended registers, XFi (16 registers)
When FPSCR.FR = 0, XF0–XF15 indicate FPR0_BANK1–FPR15_BANK1;
when FPSCR.FR = 1, XF0–XF15 indicate FPR0_BANK0–FPR15_BANK0.
6. Double-precision floating-point extended registers, XDi (8 registers): An XD register
comprises two XF registers
XD0 = {XF0, XF1}, XD2 = {XF2, XF3}, XD4 = {XF4, XF5}, XD6 = {XF6, XF7},
XD8 = {XF8, XF9}, XD10 = {XF10, XF11}, XD12 = {XF12, XF13}, XD14 = {XF14, XF15}
7. Single-precision floating-point extended register matrix: XMTRX
XMTRX comprises all 16 XF registers
XMTRX = XF0
XF1
XF2
XF3
XF4 XF8 XF12
XF5 XF9 XF13
XF6 XF10 XF14
XF7 XF11 XF15
Rev. 6.0, 07/02, page 165 of 986